U.S. patent number 5,553,671 [Application Number 08/420,101] was granted by the patent office on 1996-09-10 for piston sub for isolating drilling fluids from hydraulic fluids.
Invention is credited to Bobby G. Sieber.
United States Patent |
5,553,671 |
Sieber |
September 10, 1996 |
Piston sub for isolating drilling fluids from hydraulic fluids
Abstract
An oilfield piston sub for isolating drilling fluids from
hydraulic fluids while setting a whipstock attached to a hydraulic
packer is disclosed. The improved device reduces the number of
moving parts within existing art resulting in a more reliable
device. Once the hydraulic packer is set, the isolating piston
within the piston sub drops completely out of the way allowing
drilling fluids to exit from the bottom of the piston sub without
any impediment.
Inventors: |
Sieber; Bobby G. (Arp, TX) |
Family
ID: |
22747357 |
Appl.
No.: |
08/420,101 |
Filed: |
April 11, 1995 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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201800 |
Feb 25, 1994 |
5425419 |
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Current U.S.
Class: |
166/381;
166/153 |
Current CPC
Class: |
E21B
23/06 (20130101); E21B 7/061 (20130101); E21B
23/04 (20130101); E21B 23/01 (20130101); E21B
33/1295 (20130101); E21B 47/095 (20200501); E21B
21/00 (20130101); E21B 31/12 (20130101) |
Current International
Class: |
E21B
23/01 (20060101); E21B 33/1295 (20060101); E21B
33/12 (20060101); E21B 7/06 (20060101); E21B
23/00 (20060101); E21B 23/06 (20060101); E21B
7/04 (20060101); E21B 31/12 (20060101); E21B
31/00 (20060101); E21B 21/00 (20060101); E21B
23/04 (20060101); E21B 023/00 (); E21B
043/00 () |
Field of
Search: |
;166/381,387,308,291,153-156 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Buiz; Michael Powell
Attorney, Agent or Firm: Alworth; C. W.
Parent Case Text
This is a continuation-in-part application of U.S. Pat. Ser No.
08/201,800 filed on Feb. 25, 1994 now U.S. Pat. No. 5,425,419.
Claims
I claim:
1. An improved piston sub apparatus for isolating drilling fluids
from hydraulic fluid, used for setting hydraulic anchor-packers in
downhole operations, of the type having an upper sub mated to a
lower sub, the lower sub having upper threads for mating to the
upper sub and bottom threads adapted to mate to downhole tools
wherein the lower sub contains a sliding piston and riser
combination capable of free movement within the lower sub, the
piston having sealing means between the piston and the inner walls
of the lower sub, and in which the piston has angled fluid
passageways formed on the bottom of the piston, wherein the
improvement comprises:
an enlarged piston landing located immediately above the bottom
threads of the lower sub, said piston landing having a larger
diameter than the inner diameter of the lower sub and being longer
in height than the height of the sliding piston.
2. The improvement of claim 1 wherein said height of said enlarged
piston landing exceeds the height of the sliding piston by the
range 1/4-inch to 6 feet and wherein the diameter of said piston
landing exceeds the diameter of said piston within the range
1/8-inch to 4 inches.
3. The improvement of claim 1 wherein said enlarged piston landing
is formed by boring out the inner diameter of the lower sub
immediately above the lower threads to a length exceeding the
height of the sliding piston within the range of 1/4-inch to 6
inches and wherein the diameter of said enlarged piston landing is
larger than that of said sliding piston within the range of
1/4-inch to 2 inches.
4. An improved piston sub apparatus for isolating drilling fluids
from hydraulic fluid of the type having an upper sub mated to a
lower sub, the lower sub having upper threads for mating to the
upper sub and bottom threads adapted to mate to downhole tools
wherein the lower sub contains a sliding piston and riser
combination capable of free movement within the lower sub, the
piston having sealing means between the piston and the inner walls
of the lower sub providing isolation between the hydraulic fluid
placed below the sliding piston and the drilling fluid found above
the sliding piston, and in which the piston has angled fluid
passageways formed on the bottom of the piston, wherein the
improvement comprises:
an enlarged piston landing located immediately above the bottom
threads of the lower sub, said piston landing having a larger
diameter than the inner diameter of the lower sub and being longer
ill height than the height of the sliding piston whereby said
sealing means remains functional whenever said piston is above said
enlarged piston landing thereby providing isolation between the
hydraulic fluid and the drilling fluid, and whereby said sealing
means disengages whenever said piston is within said enlarged
piston landing thereby removing all isolation between the hydraulic
fluid and the drilling fluid.
5. The improvement of claim 4 wherein said height of said enlarged
piston landing exceeds the height of the sliding piston by the
range 1/4-inch to 6 feet and wherein the diameter of said piston
landing exceeds the diameter of said piston within the range
1/4-inch to 4 inches.
6. The improvement of claim 4 wherein said enlarged piston landing
is formed by boring out the inner diameter of the lower sub
immediately above the lower threads to a length exceeding the
height of the sliding piston within the range of 1/4-inch to 6
inches and wherein the diameter of said enlarged piston landing is
larger than that of said sliding piston within the range of
1/4-inch to 2 inches.
7. An improved piston sub apparatus for isolating drilling fluids
from hydraulic fluid, used for setting hydraulic anchor-packers in
downhole operations and whereby said isolation is no longer needed
after the hydraulic packer is set in place, of the type having an
upper sub mated to a lower sub, the lower sub having upper threads
for mating to the upper sub and bottom threads adapted to mate to
downhole tools wherein the lower sub contains a sliding piston and
riser combination capable of free movement within the lower sub,
the riser having a riser cap, the piston having sealing means
between the piston and the inner walls of the lower sub which
together with the riser cap provides isolation between the
hydraulic fluid placed below the sliding piston and the drilling
fluid found above the sliding piston, and in which the piston has
angled fluid passageways formed on the bottom of the piston,
wherein the improvement comprises:
an enlarged piston landing located immediately above the bottom
threads of the lower sub, said piston landing having a larger
diameter than the inner diameter of the lower sub and being longer
in height than the height of the sliding piston whereby said
sealing means remains functional whenever said piston is above said
enlarged piston landing thereby providing isolation between the
hydraulic fluid and the drilling fluid, and whereby said sealing
means disengages whenever said piston is within said enlarged
piston landing thereby removing all isolation between the hydraulic
fluid and the drilling fluid; and,
a heavy lubricant filling said riser in place of said riser cap
whereby said heavy lubricant will be displaced by the drilling
fluid upon arrival of the sliding piston within said piston landing
thereby forming a second conduit for the drilling fluid, assuring
that isolation between the hydraulic fluid and the drilling fluid
is completely removed after the hydraulic anchor-packer is set in
place.
8. The improvement of claim 7 wherein said height of said enlarged
piston landing exceeds the height of the sliding piston by the
range 1/4-inch to 6 feet and wherein the diameter of said piston
landing exceeds the diameter of said piston within the range
1/4-inch to 4 inches.
9. The improvement of claim 7 wherein said enlarged piston landing
is formed by boring out the inner diameter of the lower sub
immediately above the lower threads to a length exceeding the
height of the sliding piston within the range of 1/4-inch to 6
inches and wherein the diameter of said enlarged piston landing is
larger than that of said sliding piston within the range of
1/4-inch to 2 inches.
10. A method of using an improved piston sub apparatus for
isolating drilling fluids from hydraulic fluid, for setting
hydraulic anchor-packers in downhole operations having all upper
sub mated to a lower sub containing a sliding piston and riser
having a riser cap; the piston, riser, and riser cap providing
isolation between the hydraulic fluid and the drilling fluid
comprising:
a) removing the riser cap;
b) filing the lower portion of the piston sub with hydraulic
fluid;
c) filing the riser with heavy lubricant.
11. The method of claim 10 further comprising the step of placing
the piston sub on the hydraulic anchor-packer before removing the
riser cap.
12. The method of claim 10 further comprising the steps of:
a-1) placing the piston sub assembly on the anchor-packer, and
a-2) removing the upper sub before removing the riser cap.
13. The method of claim 12 further comprising the additional steps
of:
replacing the upper sub after filing the riser with heavy
lubricant, and placing the assembly into service.
Description
TECHNICAL FIELD OF THE INVENTION
The present invention relates to oil and gas drilling equipment and
more specifically relates to an apparatus and method for setting
whipstocks in an existing well bore.
BACKGROUND OF THE INVENTION
At times it is desirable to sidetrack (deviate) existing well bores
for various reasons in producing a more economical well bore. It is
well known in the oil and gas industry that whipstocks are used in
drilling to direct or deviate a drill bit or cutter at an angle
from a well bore. The well bore can be cased (lined with pipe) or
uncased (open hole; not lined with pipe). It has been customary),
to follow plug and abandonment (P&A) procedures when using a
whipstock. These P&A procedures vary as to cased or uncased
well bores. Most P&A procedures follow OCS guidelines as the
operator does not want communication between the "old" well bore
and the "new" bore. OCS guidelines would not be followed where the
operator is drilling additional "drain" bores in an existing well.
For the cased well bore, the operator will set a cement plug in the
well bore (100 hundred feet thick at a minimum) followed by a
bridge plug or EZ-drill plug. The bridge plug is a wire line device
which is set three to five feet above the casing collar (or joint)
near the required point that deviation of the well bore is needed.
The position of the bridge plug and the whipstock is critical
because the deviated hole must NOT penetrate the casing at or near
a casing collar (or joint). The whipstock is traditionally set
several feet above the bridge plug. Great care is exercised to
coordinate wire line and pipe measurements to assure that the
whipstock is clear of the casing collar (or joint). In an uncased
hole, only a cement plug of the proper length is used. The length
of the plug is determined by the depth of the uncased hole to the
point at which the deviation is required. The downhole tool is
traditionally set above the cement plug.
The complete downhole assembly generally consists of the whipstock
assembly attached to some form of packer assembly. There are
presently two conventional whipstock types available, the
"Packstock" and the "Bottom Trip". The Packstock is a whipstock and
a packer assembly that is combined to form a single downhole unit.
The bottom trip device is a single whipstock with a plunger,
sticking out of the bottom of the downhole tool, which when set
down on the bottom of the hole, will release a spring loaded slip
or wedge within the whipstock which in turn holds the too in place.
The whipstock is the actual oil-tool that causes the drill bit or
cutter to deviate from the well bore. The packer is another
oil-tool that holds the whipstock in place once the whipstock has
been set in the well bore at the desired orientation. This packer
is given the name anchor packer and it is this packer that rests
above the bridge plug in a cased hole and above the cement plug in
an uncased hole. In the case of the bottom trip whipstock, it is
the bridge plug that forces the plunger to release the spring
loaded slips or wedges; thus, holding the tool in place. It should
be apparent that there are two fundamental types of packer in use;
the first operates in a cased hole and the second operates in an
uncased hole. The bottom trip device operates only in a cased hole;
it is an old device; and, it is fraught with problems because it
has only a single slip or wedge which can work loose.
The whipstock is a triangularly shaped tool about 10 to 12 feet
long. It is slightly less then the diameter of the well bore at its
bottom and slopes so that its diameter approaches infinitely at its
top. The back of the tool usually rests against the low side of the
well bore, where the low side of the well bore is defined as that
side of the hole most affected by gravity. The tool face is
cup-shaped and guides the hole drilling equipment off to the side
of the hole in the direction set by the orientation of the tool
face. The bottom of the tool is attached to the packer.
Traditionally the whipstock must be chosen for each well bore so
that its bottom diameter matches the well bore and the packer, if
used. Its top end must match the inside diameter of the well bore
so that the drilling equipment sees a smooth transition off to the
side of the hole; and the back of the tool should match the
internal diameter of the well bore. In addition the cupped face of
the tool has been chosen to match the bore size in order to
properly guide the drilling equipment. This means that the oil or
gas field operator o must keep a stock of different whipstocks to
match the various standard well bores used in the industry.
This invention standardizes the whipstock tool to three varieties
to fit hole sizes from 33/4 inches up to 121/2 inches. The
invention proposes one style of whipstock for use with both
mechanically set packer's and hydraulically set packers. And
finally, the invention proposes an apparatus and method for
retrieval of the valuable and expensive downhole assembly after the
deviated hole is completed. This retrievable whipstock would be
invaluable in multiple drain holes in a single well bore and would
be used in both cased and open hole (uncased) conditions.
PRIOR ART
The whipstock has passed through two generations of tool since its
introduction in the early nineteen-thirties. The initial apparatus
and method of use involved a multi-step procedure. Standard P&A
procedures were followed prior to the use of the tool; i.e., the
well bore was properly plugged below the desired deviation point.
An anchor packer was then set in the hole in order to support and
maintain the orientation of the whipstock. The packer had a key
slot in its bottom which would mate with a "stinger" on the
whipstock. Wireline tools would be run into the hole to determine
the orientation of the key slot and the stinger on the whipstock
would be adjusted to match the packer key slot so that when the
whipstock was run into the hole, the whipstock would orientate
itself in the correct direction. This procedure required multiple
runs into and out of the well bore and was fraught with risk. After
the whipstock was "set", a starting mill tool would be run into the
well bore to remove attachment points on the face of the whipstock,
cut into the side of a cased hole, and generally prepare the well
bore for a deviated hole. The starting mill tool is used for about
the first twenty inches of hole. These same procedures are followed
in the next generation tool and will be explained later.
The next generation (second), which is the presently used
technique, mated the whipstock to the anchor packer. The
combination of the whipstock and the anchor packer is attached to
the drill stem using a shear pin which in turn is attached to a
raised face attachment point, known as the shear pin block, mounted
on the face of the whipstock. The downhole assembly is lowered into
the well bore until it touches bottom. (Bottom would be defined as
the bridge plug in a cased hole and the cement plug in an uncased
hole.) The assembly is then raised slightly and the orientation of
the whipstock is checked using wireline tools. The drill stem is
rotated one way or another and the orientation is checked again.
This procedure is continued until the face of the whipstock is
properly orientated. The anchor packer is then "set" in the well
bore.
There are two types of packer, mechanical set and hydraulic set.
The most commonly used packer is the hydraulically set packer. U.S.
Pat. No. 5,193,620 (Braddick) discloses a whipstock setting
apparatus and method for a mechanical packer. Mechanical packers
are "set" by applying weight to the packer which, in turn, causes
the packer slips to extend against the well bore; thus, locking (or
setting) the packer in place. This is similar to the bottom set
whipstock device in that there is a plunger extending from the
bottom of the packer; however, spring loaded slips are not used as
in the bottom set whipstock. One other difference, the bottom set
whipstock will not have any packing or resilient material that
expands against the hole to seal the lower hole section.
U.S. Pat. No. 4,397,355 (McLamore) discloses a whipstock setting
method and apparatus for a hydraulic packer. Hydraulic packers are
"set" by applying Hydraulic pressure to the packer, which, in turn,
causes the packer slips to extend against the well bore; thus,
locking (or setting) the packer in place. The hydraulic pressure is
obtained through a device called a "running tool". The running tool
converts the drill stem mud pressure to hydraulic pressure; the
hydraulic oil being run from the running tool to the hydraulic
packer through tubing to the whipstock and then through a series of
channels within the whipstock and onto the packer. The packer is
set by pressuring up the drill stem which then passes that pressure
onto the packer.
Once the packer is "set", the whipstock must be broken free from
the drill stem before any milling or regular drilling operations
may proceed. This is a simple operation--the drill stem is raised.
The packer, if properly anchored in the well bore, will not move
and the shear pin will shear. All that remains is to remove the
shear pin block which is mounted on the face of the whipstock and
to cut into the side of the well bore.
The removal of the shear pin block is undertaken by "milling". In
both the first generation and initial second generation tool a
starter mill bit is placed on the drill stem and lowered into the
well bore. The starter mill is rotated and in turn removes the
raised face. This same milling tool makes the initial cut into the
side of the casing in a cased hole. The initial milling operation
makes about a twenty inch (20") deep hole. That is to say the
operator only runs the starter mill for about twenty inches total
depth before coming out of the well bore and changing his starter
mill bit assembly. Once this first mill run is complete, the
starter mill is replaced with a second and larger mill, known as a
window mill. Another mill, known as a water-melon mill, is mounted
above the window mill. The window mill and water-melon mills
operate together to enlarge the deviated opening in the well bore
so that regular drilling operations may pass without restriction.
Generally the window/watermelon bit combination is used for seven
to ten feet into the deviated hole.
McLamore improved the second generation apparatus and method by
placing the initial mill assembly on the end of the drill stem
immediately above the whipstock. Thus, once the whipstock was freed
from the drill stem, initial milling could proceed immediately.
This was certainly an improvement because one trip into and out of
the well bore was eliminated, however, the initial milling
operation can only last about twenty inches before the mill must be
removed. This is because the setting tool, that is the piece of
metal between the mill and the whipstock which holds the whipstock
to the drill stem, will bump against the casing of a cased hole and
cause the mill to cut into the whipstock rather than the casing.
This has caused problems in the past because the whipstock face can
be damaged or the whipstock can be cut into requiring that another
complete assembly be placed in the hole.
Braddick uses the same initial milling technique as McLamore.
Braddick has other disadvantages. In a mechanical set packer, the
application of sufficient weight to set the packer is an absolute
necessity. Braddick uses the shear pin between the setting tool and
the whipstock to transfer weight to the mechanical packer. This
means that the shear pin must be carefully chosen so that it will
transfer drill stem weight to the packer for setting and yet be
sufficiently weak to shear when the drill stem is pulled upwards.
It is possible for the packer to move upward and rotate when the
stem is pulled out of the hole in order to shear the retaining pin
because the pin may be stronger than the packer retaining
force.
A major impediment for the second generation whipstock is the shear
pin block on the face on the whipstock which must be milled away so
that the face becomes a smooth cupped face. The shear pin block
ranges in size from one to one and one-half inches thick
(1"-11/2"), two and one-half to three inches wide (2"-3"), and
three to four inches long (3"-4"). It takes a considerable amount
of time to mill this block away after setting the whipstock.
Reports from the field indicate that this block can cause numerous
problems and often results in several trips with fresh starter mill
in order to remove the shear pin block and make the initial twenty
inch plus or minus (20".+-.) starting cut in the casing (or
formation).
Second generation whipstocks have further detriments. One of these
further detriments is found in the location of the shear pin itself
and the fact that this shear pin can shear if the downhole assembly
is rotated. That is, not only will the pulling force shear the pin
when shearing of the pin is required, the torsional force which
call be induced when the whipstock is being rotated in the hole can
inadvertently shear the pin. This inadvertent shearing is a
disaster! The possibility of inadvertent shearing due to rotational
forces becomes very large in a high angle well bore. Well bore
angle is defined as angle from vertical; thus, a high angle hole
approaches a horizontal bore.
A further detriment for the second generation whipstock occurs in
nearly vertical or low angle hole. The back of the whipstock must
rest against the well bore and the whipstock is designed to pivot
about a hinge pin near the bottom of the tool just above the anchor
packer. In a medium to high angle hole the whipstock easily falls
against the well bore, but in a nearly vertical hole there is
little gravity component to pull the tool against the wall. This
can cause some problems during the initial (or starting) mill
operation--that is the whipstock chatters against the well bore.
There remains an unfulfilled requirement to be able to force the
tool against the well bore in a low angle hole. The final detriment
for second generation whipstocks is that retrieval of the tool
after use is practically impossible. Retrieval of the tool will be
invaluable in modern production operations where multiple drains
are desired in a well bore. There are a number of other prior art
patents as listed in the following table that relate generally to
whipstocks.
______________________________________ U.S. Pat. No. Inventor Title
Issued ______________________________________ 2,362,529 Barrett et
al. Side Tracking 11/14/44 Apparatus 2,558,227 Yancey et al.
Sidewall Core Taking 06/26/51 Apparatus. 2,821,362 Hatcher
Extensible Whipstock 01/28/58 3,115,935 Hooton Well Device 12/31/63
4,765,404 Bailey et al. Whipstock Packer 08/23/88 Assembly
5,035,292 Bailey et al. Whipstock Starter 07/30/91 Mill with
Pressure Drop Tattletail 5,109,924 Jurgens et al. One Trip Window
05/05/92 Cutting Tool and Apparatus 5,113,938 Clayton Whipstock
05/19/92 5,154,231 Bailey et al. Whipstock Assembly 10/13/92 with a
Hydraulically Set Anchor ______________________________________
Barrett et al. disclose "Side Tracking Apparatus" or a whipstock
with roller bearings in its face. The roller bearings are meant to
force the mill against the casing. The whipstock is particularly
designed to be used with casing that has hardened such that
conventional milling techniques would not work--i.e. the mill would
probably mill into the whipstock rather than the casing. This
whipstock could be called the first of the second generation
whipstocks as it has its own set of slips built into the whipstock;
the slips being set by forcing the whipstock against the bottom of
the bore hole. The whipstock is held to its mill by a shear pin.
Tile roller bearings run the entire face of the whipstock. The
whipstock design is somewhat different then those used today ill
that the whipstock does not have an angled slope to kick the mill
into the casing (or side track the hole) but rather has a straight
offset section that runs the entire length of the desired window.
The whipstock then has a very, sharp slope at the bottom of the
whipstock which would act to shove the mill to the side.
Additionally this disclosure has no method for orientation of the
whipstock.
Yancey et al. disclose a "Sidewall Core Taking Apparatus" which
uses a whipstock to force a core taker into the side of a well
bore. The device uses a very sharp angle on the whipstock face
which requires that the core taker use a set of universal joints in
order to be able to make the bend towards the side wall. The
universal joints must be guided and the device provides a set of
roller bearings in the face of the whipstock. These bearings will
also act to improve the mechanical efficiency of the device. It
should be noted that the milling surface of the core taker does not
act on these bearings.
Hatcher discloses an "Extensible Whipstock" which is retrievable.
Tile device is not designed to be orientated ill the hole and is
set by placing weight on the whipstock; there is no releasable
device. Once the deviated hole is drilled, the whipstock will be
withdrawn from the hole with the removal of the drill string. There
is no anchor packet associated with the device and the device can
only be used at the bottom of a hole in a rocky formation into
which the whipstock can grip with a sharp point. The sharp point is
meant to prevent rotation of the whipstock during the drilling
operation.
Hooton discloses a "Well Device" which is an improvement to the
whipstock by providing a well plug at the bottom of a standard
whipstock which can be set in place "by hydraulic, pneumatic,
explosive or mechanical means." The disclosure shows an anchor
packer attached to the whipstock which in turn is attached to the
drill stem by a shear pin. The mechanical setting means is by
loaded spring action and not by setting drill string weight onto
the anchor packer. Also disclosed is a single spring which
functions to force the whipstock against the well bore. The
disclosure claims that the single spring is releasably held in
place, but does not show nor claim the apparatus to accomplish this
function. This disclosure states that the shear pin is sheared by
applying downward force to the shear pin; this method could be used
to set a mechanical packer; but, because the shear pin is broken by
the downward force, there is no method left to check and see if the
packer is properly secured in the well bore. (Normally the operator
pulls upward, if there is large movement in the drill stem, then it
is known that the packer did not set. If on the other hand there is
only slight movement--the natural spring of the string--followed by
jump, then it is known that tire packer is properly set.)
Bailey et al. ('404) disclose a "Whipstock Packer Assembly" which
is designed to be used with a single trip whipstock assembly and
starter mill. This patent is an improvement to the McLamore
device.
Bailey et al. ('292) disclose a "Whipstock Starter Mill with
Pressure Drop Tattletail" which is designed to be used with the
single trip whipstock assembly. This device causes a pressure drop
in the drill string when the starter milling operation has past a
predetermined o point on the face of the whipstock.
Jurgens et al. disclose a "One Trip Window Cutting Tool and
Apparatus" which utilizes a whipstock assembly, a window mill and
one or more water melon mills. The disclosure also states that the
whipstock slope should be between 2 and 3 degrees, but there is no
claim as to a given angle nor a statement as to why such an angle
is disclosed. The device uses a "shear pin block" which is milled
off by the water melon mill. Other parts of the disclosure are
similar, if not the same, as all other second generation
whipstocks.
Clayton discloses a "Whipstock" which will allow bore hole
deviation from the low side of the hole. The whipstock uses two
springs to force the whipstock against the top side of the hole.
The device is designed to operate in conjunction with a hydraulic
packer and the setting tool runs through the face of the whipstock.
The running tool keeps the whipstock springs in their compressed
position; the springs are released when the setting tool is
removed. The setting tool also provides hydraulic pressure to the
packer from the running tool. The setting tool is secured by
threads and release of the setting tool from the whipstock is
accomplished by "a few right hand rotations to unscrew the setting
tool conduit from the threads."
Bailey et al. ('231) disclose a "Whipstock Assembly with a
Hydraulically Set Anchor" which uses the traditional whipstock in
conjunction with an novel hydraulic packer. The hydraulic packer
utilizes a better technique to set itself in the well bore and will
remain so set upon loss of hydraulic pressure. The patent proposes
two methods of setting the assembly. The first uses a method for
setting the assembly without a starter mill; thus, requiring a
minimum two pass operation. The second calls for setting the
assembly with a starter mill in place which results in a minimum
one pass operation. In general this patent is an improvement to
previous devices disclosed by Bailey et al.
Thus, the prior art has left a number of disadvantages:
it is difficult to use a mechanically set packer, which is cheaper
than the hydraulic packer.
the retaining shear pin can inadvertently shear when the whipstock
is being positioned within the well bore.
the raised face of the mounting attachment to the whipstock face
(shear block) must be milled off before any deviation operations
can commence.
the whipstock assembly must be specifically designed to fit the
given dimensions of the well bore; thus, many sizes must be
warehoused.
it is easy to mill into the face of the tool during the initial (or
start) milling operation.
there is no method of using an MWD (Measurement While Drilling)
Tool to determine whipstock orientation: only wireline techniques
can presently be used.
In summary therefore, existing whipstocks used with sidetracking
(or deviation) operations are inflexible as to various well bore
sizes and the different conditions encountered downhole. This
inflexibility leads to increased manufacturing costs and added risk
of failure because the whipstock is extended beyond its design
criteria. This invention resolves a number of inflexible
constraints.
SUMMARY OF THE INVENTION
The whipstock of this invention can be permanent or retrievable and
consists essentially of a setting tool which holds the whipstock
assembly to the drill stem, a deflector head which attaches to the
top of the whipstock body and is sized to the diameter of the bore,
a whipstock body which is available in three size, and an optional
bottom end spacer. There is no shear pin block on the face of the
whipstock that must be milled off; initial starting guidance for
the window mill is provided by the deflector head. The deflector
head, which varies between one foot and two feet long depending on
bore hole size, is furnished in hardened steel with optional PCD
(polycrystaline diamond) inserts. The hardened surface with or
without the optional inserts severs to stop the initial milling
operation from cutting into the whipstock and, as stated, further
force the mill against the well bore. The whipstock body has a
retrieval system centered at the mid point of the body which will
interlock with a fish hook to allow for retrieval of the whipstock,
deflector head and anchor packer. The whipstock incorporates a set
of springs in the hinge which are held in a compressed state until
the unit is set at which time the springs can be released to help
hold the back of the whipstock against the well bore. The whipstock
body and setting tool are adapted to operate with either a
mechanically set anchor packer or a hydraulically set anchor packer
with the choice being made in the field.
In addition to providing for an improved and workable tool, an
object of the invention is to minimize required oil tool inventor),
which is accomplished by using three body sizes, 8", 51/2" and
31/2, for the whipstock. Thus, three whipstock bodies can be used
for bore holes from 31/4" through 121/2. The deflector head, which
is attached to the top of the whipstock body and occupies at least
the topmost one foot of the whipstock assembly, allows for
different bore sizes within the range of the three whipstock
bodies. An optional spacer may be required at the bottom of the
whipstock, below the hinge, to take up the gap between the
whipstock body and the well bore.
When the whipstock is used with a mechanically set packer, it is
easy to use MWD (Measurement While Drilling) tools for whipstock
tool face orientation. Mud circulation is maintained through the
port ill the running tool that is normally used for hydraulic oil
when the downhole tool is used with a hydraulically set packer. Of
course standard wire line orientation techniques are still useable
for tool face orientation. MWD is possible with a hydraulic packer,
but all additional tool incorporating a pinned by-pass valve would
be required because the exit port on the running tool would be
attached to the hydraulic system.
The whipstock incorporates a special slot (setting/retrieval slot)
in the face of the tool which starts just below the deflector head
and runs to approximately the mid point of the tool. The slot is of
variable depth because the tool face has an angle and the slot is
to form a perpendicular exit into the tool face. The setting tool
fits into this slot and bottoms at the bottom of the slot. The
setting tool is held in place by a shear pin located near the
bottom of the slot, which enters from the tool back and is screwed
into the setting tool. Thus, vertical force can readily be asserted
on the tool and anchor. If the force is in the downward direction,
that force is transferred directly to the tool and anchor. If the
force is upward, the shear pin must bear the force or fracture. Oil
the other hand, if the force is torsional, then that torsional
force is transferred to walls of the setting slot.
The setting slot also acts as a guide for the retrieval tool. A
retrieval slot is located slightly above the bottom of the setting
slot. Tile retrieval slot runs from the front of the setting slot
to the back of the tool and is designed to fit about a hook located
on a specially designed retrieval tool. The retrieval tool has an
opening in the hook face which allows drilling fluid to pass
through it. Thus, MWD tools can be used in conjunction with the
retrieval tool to help in establishing hook orientation. The hook
also has a spring loaded/pinned valve which is designed to close
when the hook properly engages the retrieval slot. Closure of this
valve will cause a pressure pulse at the surface which tells the
operator that the retrieval tool has properly engaged the
whipstock. The hook is further designed so that it tends to
straighten out the whipstock when a pulling force is applied. A
properly designed whipstock is meant to fall against the "backside"
of a well bore and if the tool is not pulled straight, then the top
of the tool will catch against each joint in the casing. The
retrieval tool helps reduce this problem.
Finally, there is an integral spring loaded shear pin within the
retrieval tool which is designed to prevent inadvertent release of
the retrieved whipstock while reciprocating the whipstock in order
to help it past an obstruction in the well bore. The spring loaded
shear pin springs into a matching cavity within the
setting/alignment slot within the tool face of the whipstock as the
retrieval tool fish-hook properly engages the retrieval slot. The
spring loaded shear pin prevents independent downward motion
between the whipstock and the retrieval tool; thus, locking the
fish-hook in place. Note that the spring loaded pin can be sheared;
thus, allowing for "controlled releasability".
The further advantage to this design is the "controlled
releasability" of the Retrieving Tool. The spring loaded shear pin
will shear and allow the retrieval tool to disengage from the
whipstock whenever sufficient downward weight is applied to the
drill string. Complete retrieval is then performed by slacking off
the retrieval tool which will back away from the retrieval slot
because the hook is tapered from its base to its face and then
rotating the drill string by a quarter turn, thus, turning the hook
of the retrieval tool away from the slot. As the hook initially
pulls away from the whipstock, the wash port(s) will open and at
the same the mud circulation pumps can be re-started. The excess
mud pressure appearing at the wash port(s) will be a tremendous aid
in releasing the hook from the whipstock.
The method of use is relatively simple. First, one of the three
body sizes of whipstock is chosen to most closely match the well
bore. Second, a deflector head is chosen that matches the well bore
and is secured to the appropriate whipstock. Third, the proper
sized anchor packer is chosen that most closely matches the well
bore and, if required, the optional bottom spacer is bolted to the
whipstock body. Finally the running tools must be chosen. If the
anchor packer is hydraulic, then both a setting tool and an
improved piston sub are required; however, only the setting tool is
required for a mechanical anchor packer. The setting tool is sized
to the appropriate whipstock body and the same tool severs for both
mechanical or hydraulic packers. The complete downhole tool is
assembled in the standard manner on the drill floor/rotary, table
with proper attachment made between the whipstock and the setting
tool via a shear pin. The downhole tool is then lowered into the
well bore.
In the case of the mechanically set packer/whipstock downhole tool
assembly, the tool is lowered into the well bore until it hits
bottom. The drill string is then raised, as per standard
procedures, and mud circulation started. The circulation allows
orientation signals from the MWD tool to pass to the surface. The
drill string is then manipulated until the proper orientation is
obtained. The packer is then set by placing the required weight on
the downhole assembly. Orientation could be checked immediately
after setting by MWD. The drill stem is pulled free from the
whipstock and the string is returned to the surface. Note that
standard wireline orientation techniques call still be
utilized.
The running tool is replaced and a window mill and watermelon
mill(s) run into the hole; there is NO need for a starting mill as
there is no shear pin block to remove from the face of the
whipstock. Standard milling techniques follow and the initial side
track established. The milling tools are then removed and regular
drilling operations begun. Thus, the whipstock invention still
results in a two-pass operation as does the present second
generation device unless the operator wants to enlarge the window
beyond that obtainable with the second pass.
In the case of the hydraulic set packer, the complete downhole tool
is assembled and attached to its setting tool. The setting tool is
ill turn attached to a piston sub tool which converts mud pressure
to hydraulic pressure ill order to set the packer. Hydraulic tubing
is run through the channels provided in the whipstock and connected
between the setting tool/running tool assembly and the hydraulic
packer. All other installation details are the same as presently
used ill the industry. Note that standard wireline techniques must
be used for tool face orientation with the hydraulic packer. It is
possible to use MWD techniques to orientate to tool face; however,
experience has shown that there are high failure rates with the
downhole tool which permits the use of MWD with hydraulic running
tools, known as pinned by-pass valves.
Retrieval of the whipstock is relatively straightforward for
operators who are experienced with "fishing techniques." The
retrieval tool is attached to the bottom of a downhole string which
includes all MWD tool and ally required fishing jars. The drill
string is run into the hole and circulation is maintained. In the
area of the whipstock, the retrieval tool is orientated to closely
align with the setting slot which acts as the tool guide for the
retrieval tool. The mud port in the retrieval hook guides the
circulation in such a manner that the setting slot and retrieval
slot can be flushed clear of any debris (cuttings, sand, etc.) that
could interfere with the retrieval operation. The drill string is
then lowered until it `bottoms`; the drill string is then raised
which causes the hook to pull into the retrieval slot. As soon as
proper engagement is made with the retrieval slot, the mud port
valve(s) close, which send(s) a pressure pulse to the surface
announcing engagement of the retrieval slot. At almost the same
time, the spring loaded shear pin will latch the retrieval tool
into the whipstock. Mud circulation should cease and the drill
string raised to set the retrieval tool into the retrieval slot.
Note that the spring loaded shear pin which locks into the face of
the setting slot can be used as a landing point in order to "reset"
any fishing jars that may be included in the downhole retrieval
assembly. Tile weight required to shear this locking pin is much
higher than the weight needed to re-set the fishing jars: thus,
"controlled releasability"; is maintained.
As the drill string is raised, the pulling force should increase.
All increase in pulling force is a second indication of engagement.
With the retrieval tool properly engaged and as the tool is pulled
upward, the hook will move further back into the retrieval slot and
pull the whipstock tool face into alignment with the whipstock base
and anchor. Additionally, the extra length of the hook will extend
beyond the whipstock back assuring that the tool top will not rub
against the well bore. This means that the chances of the tool top
(or head) catching against each and every casing joint are
substantially reduced. The optional fishing jars can be reset as
needed in order to assist in the retrieval of the whipstock.
The anchor packer used with a retrievable whipstock, be it
mechanically set or hydraulically set, is chosen so that it
incorporates shear screws in the upper set of slips (or wedges). As
the whipstock/packer is raised, the pulling force will increase and
shear the upper slip shear screws. This releases the upper slips on
the anchor packer and the packer can now move upward. As the packer
moves upwards, the packing will collapse as the packer extends
against the bottom set of slips, which should release. It should be
noted that the lower set of slips on a packer are designed to grip
in the downward direction; thus, if the lower slips do not release,
the packer can still be pulled out of the well bore. The entire
whipstock/packer assembly is now free to be withdrawn from the well
bore and a standard trip operation now follows.
It should be noted a setting slot and, if necessary, a retrieval
slot can be manufactured or placed in the tool face of existing
whipstocks. In fact existing warehouse stock could be modified in
the field to incorporate a setting slot and a retrieval slot. This
would allow the techniques described above to be used with second
generation whipstocks. This concept will be discussed at a later
time.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of the WHIP-ANCHOR used with a
mechanical packer whose OD is approximately the same as the
WHIP-ANCHOR.
FIGS. 1AA through 1EE are cross-sectional views of the WHIP-ANCHOR
taken at the lines indicated in the main figure
FIGS. 1A through 1E are cross-sectional views of the WHIP-ANCHOR
taken at the lines indicated in the main figure showing the prior
art.
FIG. 2 is an elevational view of the WHIP-ANCHOR used with a
hydraulic packer whose OD is larger than the WHIP-ANCHOR. This
figure serves to illustrate a variant of the WHIP-ANCHOR system
which uses the optional spacer.
FIGS. 2AA through 2FF are cross-sectional views of the WHIP-ANCHOR
taken at the lines indicated in the main figure
FIGS. 2A through 2F are cross-sectional views of the WHIP-ANCHOR
taken at the lines indicated in the main figure showing the prior
art.
FIG. 3 is a frontal elevational view of the WHIP-ANCHOR system
looking directly at the tool face and used with a mechanical packer
whose OD is larger than the WHIP-ANCHOR. The illustration shows the
prior art profile.
FIGS. 4A through 4D show a series of views the deflector head used
on the WHIP-ANCHOR system.
FIGS. 5A through 5C show a series of views of the WHIP-ANCHOR,
hinge pin, hinge springs, and spring retainer shear pin.
FIGS. 6A through 6C show the details of the optional spacer
block.
FIG. 7 is a side elevational view of the WHIP-ANCHOR system
attached to its respective variant of the Mechanical Setting
Tool.
FIG. 8 is a side elevational view of the WHIP-ANCHOR system
attached to its respective variant of the Hydraulic Setting
Tool.
FIG. 9 gives details of attachment of the Setting Tool to the
WHIP-ANCHOR.
FIG. 9A is a cross-sectional view of the Setting Tool within the
WHIP-ANCHOR setting slot taken at AA in FIG. 9.
FIGS. 10A and 10B show construction details for the preferred
embodiment of the setting tool using a setting bar and tubular
welded to a top sub.
FIGS. 10C and 10D show construction details for an alternate
embodiment of the setting tool using a setting bar welded to a top
sub with space for attachment of a hydraulic hose.
FIG. 11A is a front view of the lower portion of the setting slot
giving the location of the retrieval slot.
FIG. 11B is a side sectional view of the lower portion of the
setting slot shown in FIG. 11A.
FIG. 11C is a side sectional view of the setting and retrieval slot
shown with the retrieval tool latched ill place.
FIG. 12A is a side sectional view of the First Embodiment of the
lower section of the retrieval tool.
FIG. 12AA is a cross section of the First Embodiment of the
retrieval tool taken at AA/AA in FIG. 12A.
FIG. 12B is a side sectional view of the Second Embodiment of the
lower section of the retrieval tool.
FIG. 12BB is a cross section of the Second Embodiment of the
retrieval tool taken at BB/BB in FIG. 12B.
FIG. 12C is a cross sectional view of the Piston Sleeve Valve to be
used with the
Retrieval Tool of FIG. 12A or FIG. 12B and illustrates the
preferred positive retrieval tool engagement indicator.
FIG. 12CC is a section view of the Piston and Surrounding Spring of
the Piston Sleeve Valve taken at CC in FIG. 12C.
FIG. 12D is a frontal view of the hook face of the retrieval tool
taken at C/C in FIG. 12A or FIG. 12B.
FIG. 13A illustrates a first alternate to a positive retrieval tool
engagement indicator which is shown on a tool using the First
Embodiment of the lower section of the retrieval tool.
FIG. 13B illustrates a second alternate to a positive retrieval
tool engagement indicator which is shown on a tool using the Second
Embodiment of the lower section of the retrieval tool.
FIG. 14A shows the preferred embodiment of the retrieval tool
latching mechanism with the retrieval latch pin in the body of the
whipstock and the receiving slot in the body of the retrieval
tool.
FIG. 14B shows an alternate embodiment of the retrieval tool
latching mechanism with the retrieval latch pin in the body of the
retrieval tool and the receiving slot in the body of the whipstock
(the reverse of FIG. 12A).
FIG. 15A shows the retrieval tool near the top of the WHIP-ANCHOR
about to be orientated to scrub the setting slot.
FIG. 15B shows the retrieval tool with its hook face facing the
setting slot at the beginning of the scrub of the setting slot.
FIG. 15C shows the retrieval tool near the bottom of the setting
slot immediately prior to bottoming out on the base of the slot and
prior to pulling up to engage the retrieval slot.
FIG. 15D shows the retrieval tool fully engaged ill the retrieval
slot, retrieval latching mechanism aligned and latched, and with
the hook extending through the back of the WHIP-ANCHOR: thus,
drawing the back of the WHIP-ANCHOR away from the well bore.
FIGS. 16 through 19 show details for the setting tool showing how
one tool is used for both mechanical and hydraulic operations.
FIGS. 16 and 17 show the First (or Preferred) Embodiment of the
setting tool, whereas FIGS. 18 and 19 show the Second (or
Alternate) Embodiment of the setting tool, both respectively used
for setting Mechanical and Hydraulic Packers.
FIG. 20 shows details for the making tip of the running arrangement
for the WHIP-ANCHOR with a mechanical packer which includes the
setting tool, MWD, etc.
FIG. 21 shows details for the making up of the running arrangement
for the WHIP-ANCHOR with a hydraulic packer which includes the
setting tool, the standard wireline orientation sub, etc.
FIG. 22 shows details for the making tip of an alternative running
arrangement for the WHIP-ANCHOR with a hydraulic packer which
includes the setting tool, MWD, a pinned by-pass sub, etc.
FIGS. 23 and 24 show the drill stem, setting tool, and downhole
assembly in place
in a well bore before shearing the shear pin for a Mechanical and
Hydraulic Packer respectively.
FIGS. 23A and 24A show the respective prior art.
FIGS. 25 and 26 show the drill stem, setting tool, and downhole
assembly in place in a well bore after shearing the shear pin at
the end of the first pass for a Mechanical and Hydraulic Packer
respectively.
FIGS. 25A and 26A show the respective prior art.
FIG. 27 shows the complete milling assembly at the beginning of the
second pass operation in a cased well bore for either a Mechanical
and Hydraulic Packer respectively.
FIGS. 27A and 27B show the prior art.
FIG. 28 shows the complete milling assembly at the end of the
second pass operation illustrating the open window in a cased well
bore for either a Mechanical and Hydraulic Packer respectively.
FIG. 29 shows a cross section of a "Sub with Piston" Bottom Hole
Assembly (BHA) running tool which is used in the preferred method
for setting a WHIP-ANCHOR with a hydraulic packer.
FIG. 30A is an enlarged view of the Piston of FIG. 29.
FIG. 30B is a bottom view of the Piston of FIG. 29.
FIG. 31 illustrates a proposed Bottom Hole Assembly (BHA) assembly
for use with the retrieval tool.
FIG. 31A illustrates the alternate make up if an orientation sub is
used in the place of and MWD tool.
FIG. 32 illustrates an alternate embodiment for the setting tool
and setting slot which considers problems raised if the strength of
material becomes a factor.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention will be described in detail in what is termed
as a two pass operation in which the whipstock (the item of the
invention) and an anchor packer (be it a hydraulically or
mechanically set packer) are releasably secured to a setting tool
and any other required tools, all of which are in turn, connected
to a drill string. The entire downhole whipstock and anchor-packer
assembly will be referred to as a Whip-Anchor in this
discussion.
A two pass operation begins when the drill string, with the
Whip-Anchor attached via a setting tool, is lowered to the desired
level in a well bore and then manipulated and so that the whipstock
faces in the desired direction. The drill string is then further
manipulated to set the anchor packer which in turn holds the
whipstock in the desired orientation in the well bore. Once the
packer is properly set the drill string is freed from the
Whip-Anchor by pulling upward oil the drill string. The drill
string is withdrawn from the hole: thus, completing the first
pass.
In a cased hole, a window and watermelon mill assembly is then
placed on the drill string and the drill string lowered into the
well bore for the second pass operation. (Note that the window and
watermelon mill assembly generally consists of a single window mill
and one or more watermelon mills.) The drill string is then used to
cut a window in the casing for drilling the well bore in a deviated
direction. Once the window is complete the drill string is
withdrawn from the hole; thus, completing the second pass. If the
well bore is open hole or uncased, the second pass may be omitted
and regular deviated hole drilling may be commenced. All of these
procedures are well known in the art and the main discussion of
this invention will center about its use in cased holes. It should
be understood that this discussion does not serve to limit the use
of the invention in cased holes; but only serves to aid in the
description of the device and method where needed comments will be
made about the apparatus and its use in open hole.
In discussing multiple pass operations for setting the prior art
whipstock or the instant invention, it must be realized that,
although preparation of the bore hole is critical, proper
preparation of the bore hole is NOT considered to be a part of the
setting operation for a whipstock. The well bore must be clean and
free from any and all obstructions and hole conditions must be
known. (That is: size of casing, if cased; type of cement: where
cement is: formation type: etc.) The term "hole conditions" is a
term well used in the art and also refers to the ability to
circulate drilling fluids in the well bore.
Part of the preparation for setting a whipstock involves making a
trip into the well bore with a full gauge taper mill plus two full
gauge watermelon mills (a so called "locked up bottom hole
assembly") to below the point of planned sidetrack. A "trip" is a
term of art which describes entering a bore hole with a drill
string and exiting the bore hole, although the term can be used for
a "one-way trip". Once the bottom hole assembly is below the
planned point, drilling fluid is circulated until the hole is
clean. A "clean hole" is readily determined by those skilled in the
art of well bore drilling by observing circulation rates, pump
horse power requirements, mud plasticity (rheology), net weight on
bit, as the bottom hole assembly is lowered and raised in the hole,
etc. If the hole conditions do not allow free movement
(reciprocation) of the drill string and bottom hole assembly, then
the planned setting of the whipstock should be abandoned. Those
skilled in the art of setting whipstocks know that running a
whipstock/packer assembly into a well bore with unknown conditions
is foolish and dangerous.
Well bores are notorious for collapsing, for having highly twisted
conduits, and other myriad problems. Thus, when the actual
whipstock is run into the well bore, it is often necessary to
rotate the whipstock/anchor assembly and reciprocate that assembly.
The same may be said when a whipstock is retrieved from a well
bore; thus, the retrieval tool must be capable of retaining the
whipstock/packer assembly during reciprocation of the drill
string.
The current technique of mounting the whipstock to the drill string
via a shear pin and shear block does not prevent torsional shear on
the pin, nor does the method allow for large downward exertion of
force on the whipstock: thus, the shear pin can shear when it
should not! This invention resolves these problems; however, it
does not resolve the upward exertion of force because the shear pin
must shear at a given force which may be less than the force needed
to free a stuck whipstock. The mere fact that increased downward
force is available could save a well bore if the whipstock becomes
stuck. This is because the stuck whipstock can be forced to the
point of deviation, orientated and used: or the stuck whip-stock
could be forced below the point of deviation and abandoned.
In sidetracking well bores, the deviation to the new were path must
be established from the old well bore. This can be accomplished by
setting the present art whipstock/packer assembly and proceeding
through a series of milling operations. The amount of deviation of
the new well path from the old well bore path is limited by the
strength of materials from which the mill bodies are made, when
using rotary drilling techniques to sidetrack the old well bore.
These mill bodies can only withstand a certain amount of bending
(or flexing) stress before they fracture.
Experience has shown that:
33/8" OD mill bodies which are used on hole sizes from 33/4" OD to
51/4" 0D will safely withstand a maximum of 2.5 degrees of
deflection per 100' whist milling:
43/4" OD mill bodies which are used on holes sizes from 51/4" OD to
71/8" OD will safely withstand a maximum of 3 degrees of deflection
per 100' whist milling:
61/2" OD mill bodies which are used on holes sizes from 77/8" OD to
991/2" will safely withstand a maximum of 6 degrees of deflection
per 100' whist milling; and
8" OD mill bodies which are used on holes sizes from 91/2" OD to
121/2" OD will safely withstand a maximum of 12 degrees of
deflection per 100" whist milling.
Thus, current whipstock manufactures adjust the Tool Face slope to
meet these criteria; however, each sized whipstock has its own
particular slope and body size. When a whipstock is set in a well
bore, it is centered within that well bore. The hinge in a
whipstock allows the centered whipstock to drop or fall against the
well bore so that the top has no gap and the mill "sees" a
continuous surface that is properly deflected at the correct
slope.
The inventor has noted that the "effective tool face slope" will
increase whenever the tool drops against the back of the well bore.
Advantage of this fact can be taken by proposing three (or more)
Whip-Anchor types. For example, in an 81/4" ID bore, with a
Whip-Anchor having an 8" OD body and having a tool face slope of
3.18 degrees, the effective tool face slope will increase to about
3.28 degrees. This is because the back of the tool falls against
the well bore: thus, increasing the deflection angle. The resulting
"effective tool face angle" is well within the constraints listed
above. In a similar manner, in a 121/2 "1ID bore using a
Whip-Anchor having an 8" OD the effective tool face angle will
increase to about 4.07 degrees. But again, this effective angle is
well within the above listed constraints.
Similar examples can be stated for other sizes of well bore and the
inventor proposes that three types (or sizes) of Whip-Anchor will
safely and effectively operate in common well bores sized from 33/4
inches to 121/2 inches. This concept could readily be extended to
larger (or smaller) bore sizes and the choice of three types of
Whip-Anchor should not be taken as a limitation on the invention.
These three types will cover the most commonly encountered well
bores in the industry and will serves to reduce inventory stock of
whipstocks. With all these points in mind the instant invention,
which is a series of singular small inventions and improvements
forming a workable downhole tool, will be described.
Attention is first directed to FIG. 1, FIG. 2, and FIG. 3 of the
drawings which illustrate the instant invention as it would appear
prior to being placed inside a well bore. FIGS. 1 and 2 show a side
elevational view and a series of cross-sectional views of the main
part of the instant invention, namely the improved whipstock
mounted to a mechanical packer (FIG. 1) and to a hydraulic packer
(FIG. 2). There is little difference between the two Whip-Anchors
in FIGS. 1 and 2 as regards the whipstock. Very little discussion
of the packer will be undertaken since it does not form a part of
this invention; however, the type of packer used does affect the
`plumbing` of the instant invention and the make-up of the tools
used to manipulate the Whip-Anchor. FIG. 3, on the other hand,
shows a front elevational view of the tool attached to a mechanical
packer which is the simplest embodiment of the instant
invention.
The invention, as previously stated is a series of inventions which
make up a complete system (apparatus) and a series of methods for
setting anti retrieving Whip-Anchors. The system is made up of:
A deflector head.
A whipstock body with a spring hinge section,
An optional spacer,
A cross-over sub, and
A mechanical packer, and A mechanical setting tool, or
A hydraulic packer, and A hydraulic setting tool, and an improved
piston sub, or
A retrieving tool, pills
Other necessary, (existing) drill string tools.
Starting with FIG. 1 and FIG. 3, which illustrate the instant
invention in its simplest embodiment, the top of the tool body, 4,
is shown with its deflector head, 7, in place. The deflector head
is further illustrated in FIGS. 4A-D and will be discussed in
detail later. The deflector head, 7, is mounted to its whipstock
body, 4. Both the deflector head and the whipstock body must be
chosen to fit the particular well bore size, 30. FIGS. 1AA through
1EE (as well as 2AA through 2FF) show cross-sectional views of the
whipstock body; the equivalent prior art cross-sectional views are
shown on the left-hand side of the illustration. Tile difference
between the prior art and the instant invention are clearly
illustrated. In the prior art the cupped or curved face, 11, of the
whipstock ran completely from one side of the well bore to the
other side; the inventor has discovered that this complete cupped
face is not necessary, and that a shortened version as shown in the
cross-sectional views will suffice. Oil the other hand the
deflector head. 7, must run from side to side of the well bore in
order to deflect the window mill to the side of the well bore. Once
the window mill has started its cut into the well bore side, it
need only be guided by the partial cupped face of the instant
invention. The fulcrum effect of the drill string will also aid in
directing the window mill to the side of the well bore. This
discovery further means that a single whipstock body can serve in a
number of different sized well bores which is completely different
from the prior art in which a whipstock body could only be used in
a given bore size for which the body was designed. Thus, the
inventor contemplates three types (or sizes) of whipstock bodies as
given in the table below, which will operate in well bores from
33/4 inches to 121/2 inches.
TABLE 1 ______________________________________ WHIP-ANCHOR TYPE (OR
SIZE) AND PARAMETERS Fits Fits Type Body Size Bore Size Casing Size
Tool Face Whipstock Inches Inches Angle Curvature
______________________________________ I 31/2 33/4-51/2 41/2-65/8
2.09.degree. 51/2 II 51/2 53/4-8 7-85/8 2.62.degree. 8 III 8
81/4-121/2 95/8-133/8 3.18.degree. 121/2 C other as needed
______________________________________
It should be noted that the given sizes of well bore are in common
use and these sizes are not intended to act as a limitation on the
invention, as the concept could easily be extended to smaller or
larger bores by the simple expedient of changing the size of the
body. In a similar manner additional body sizes could be inserted
in the table so that the optional spacer, to be discussed, would
become unnecessary. The actual whipstock body would be manufactured
using current materials and techniques. A mild steel will be used;
however, the tool face should have a hardened surface formed from
Tungsten Carbide to resist wear. The finishing technique goes by
such trade names as "Clusterite" or "Zitcoloy". These are
proprietary and well established welding techniques for placing a
hard finish on a surface that will resist wear.
As a specific example of whipstock configuration consider that the
operator is cutting an 81/2 inch window and drilling a new well
path from 47 PPF (pound per foot) 95/8 inch casing. The deflector
head must match the ID of the 95/8 inch casing and its tool face
must match the 81/2 inch window mill. This deflector would be
mounted on a Type III whipstock whose back face will have a
curvature of 8 inches and whose tool face will have a curvature of
121/2 inches with a tool slope angle of 3.18.degree. . These
dimensions are given for example only and are not to be considered
a limitation on this invention.
The deflector head, shown in FIGS. 4A-4D, must be sized to fit the
bore of the well bore. The object of the deflector head is to
"shove" the initial window mill into the side of the bore. It has
been noted that the initial milling operation places severe wear on
the top section of a whipstock. Thus, the deflector head is made of
hardened steel with optional PCD (polycrystaline
diamond--industrial diamond) inserts in the face of the head, 51.
The deflector head length, 58, ranges in length from about one foot
to about two feet; the actual length being determined by the bore
size. For example in a 31/2 inch bore size, the head should be
about one foot long; whereas in a 121/2 inch bore size the head
should be about two feet long. The back of the deflector head, 57,
is shaped to match the bore. That is, the back of the head will lie
"flat" against the cupped surface of the bore. The leading edge,
50, of the head is about 1/16 inch thick and matches the bore at
its backside.
Starting from the leading edge and running down to the joint, 52,
between the deflector head and the whipstock body, the tool face
slopes outward from its back, forming a cupped surface with a tool
face slope ranging from about two degrees (2.degree.) to about 4
degrees (4.degree.). The actual tool face slope will depend on the
bore size, the deflector head length and the whipstock body tool
face angle. For example the deflector head would have a tool face
angle chosen to match the 2.09.degree. angle found in the Type I
whipstock, the 2.62.degree. angle found in the Type II whipstock,
and the 3.18.degree. angle found in the Type III whipstock.
As specific example of deflector head configuration, if the
operator is cutting an 81/2 inch window and drilling a new well
path from 47 PPF (pound per foot) 95/8 inch casing, then the
deflector head back would have curvature to match the ID of the
95/8 inch casing--namely 8.681 inches. Tile deflector head tool
face would have 81/2 inch curvature with a 3.18.degree. tool face
slope angle and the length would be just over 16 inches. Again, it
must be noted that these angles and dimensions should not be taken
as a restriction on the invention as they only serve to give the
best known tool face parameters as set by the bore conditions. If
larger or smaller bores are in use, these parameters would have to
be changed.
The deflector head will be manufactured from 4340 steel or from a
material that has a similar hardness. Optional PCD inserts, 51, are
placed in the standard pattern to minimize wear and actually can be
considered as acting as a bearing surface for the window mill.
Techniques for the insertion of PCD inserts and heat treating of
metal to maintain a given hardness are well known in the art and
will not be discussed.
The deflector is attached to the whipstock body by pins, 53,
press-fitted into holes, 54, in the whipstock body. As the
deflector head will suffer considerable vibration when the window
mill is on it, a number of pins will be needed and most likely the
two sections will be welded to each other along the back junction
gap, 60 and 69. The weld must be ground to match the back curvature
of the deflector head. FIG. 4B clearly illustrates the deflector
head attached to the whipstock body when the head and the body are
of equal curvature, i.e. 31/2" body to 31/2" deflector head, 51/2"
body to 5,1/2" or 8" body to 8" deflector head. FIG. 4C and FIG. 3
illustrate the larger deflector OD when attached to the smaller
whipstock body OD, i.e. a 121/2" deflector head attached to the
Type III or 8" body.
TABLE 2 ______________________________________ DEFLECTOR HEAD
PARAMETERS WHIP-ANCHOR Thickness at Type and Size Slope Length
Connection ______________________________________ I - 31/2" OD 2.09
133/4" 1/2" II - 51/2" OD 2.62 161/2" 3/4" III - 8" OD 3.18 18" 1"
______________________________________
A table of recommended dimensions of the three deflector heads that
the Whip-Anchor system will require is given above. The radius of
curvature for the backside of the various deflector head is not
given because the required radius will be set by the bore ID in
which the head is being used. A person skilled in the art of
drilling well bores can easily supply the required radius
remembering that the backside radius of curvature must be chosen so
that the backside of the deflector head rests firmly against the
bore. This, of course, will require a proper radius of curvature
equal to that of the ID of the bore and a curved cone shape across
the top side of the deflector head. All of these calculations are
currently practiced and well known. The table is given for
illustration only and is not intended to serve as a limitation on
the instant invention. As previously noted, the sizes types) of
whipstock can be modified to fit larger or smaller bores than those
presently discussed.
The Setting Tool Slot, 13, can be found starting at or a couple of
inches below the deflector head to whipstock body joint, 26. The
relative position of the setting slot can best be seen in FIG. 3.
The setting tool slot is about one inch (1") wide in the type I
tool, about one and one half inches (11/2") wide in the type II
tool, and about two inches (2") wide in the type III tool. The
width is actually determined by strength of material considerations
based on the force required to set a mechanical packer and by the
retrieval tool slot (these considerations will be discussed). The
setting slot has a variable depth determined by the tool face
angle. The back of the setting tool slot is perpendicular to the
base of the whipstock and parallel to the back of the whipstock;
thus, its variable depth as the slot continues towards the base of
the whipstock. The slot terminates above the mid point of the
whipstock. The actual termination point, 25, is determined by the
type of whipstock (Type I, II or III) and is set by the properties
of strength of materials. The depth of the slot at the bottom will
range from about V2-inch in the Type I tool to about 1 inch in the
Type III tool.
TABLE 3 ______________________________________ SETTING TOOL
PARAMETERS WHIP- Thick- Deflec- ANCHOR Setting Slot ness to tion of
Type and Length, Width, Back of Milling Size Slope Depth Tool Tool
______________________________________ I - 2.09 221/4" .times.
11/32" .times. 1/2" 1.31" 31/2" OD 0.81 II - 2.62 191/2" .times.
15/32" .times. 3/4" 1.65" 51/2" OD 0.90" III - 8" OD 3.18 18"
.times. 21/32" .times. 1" 1" 2.00"
______________________________________
A recommended set of parameters is given in the table above for the
setting slots used in the three types of While-Anchor system. These
parameters are given to illustrate the instant invention and should
not be considered as limitations on the present invention. If
additional types of Whip-Anchor are proposed, the same constraints
that apply to the example table below will yield the required
parameters for smaller or larger Whip-Anchor types.
In the table above, the column entitled "Deflection of the Milling
Tool" denotes the distance the Whip-Anchor Tool Face has moved the
Window Mill into the casing (or bore side wall in an uncased hole).
And the column entitled "Thickness to Back of Tool" is the distance
measured at the bottom or base, 25, of the setting slot from the
setting slot face to the tool back (this is shown as length 66 in a
number of Figures).
It should be noted that all setting slots should end at the setting
slot base, 25, at about thirty-six inches (36") from the top of the
Whip-Anchor. The setting slot length is restricted because the
milling tool must be able to fulcrum (lever) off of a smooth cupped
face in order to properly guide the milling operation on its
deviated trajectory. (Additional discussion on trajectory appears
later in this discussion.)
The setting slot also provides access to the retrieval slot, 12,
which runs from the face of the setting slot at an upward angle and
exits at the back of the whipstock body. The retrieval slot is the
same width as the setting slot and its bottom starts from about
11/2 to 21/2 inches above the bottom of the setting slot extending
upward for about 10 inches. These dimensions depend on the Type of
Whip-Anchor and will be discussed along with the retrieval slot and
its function in a later portion of this discussion. Slightly above
the retrieval tool slot, 12, is the location of the retrieval tool
shear pin aperture or mechanism, 27; the choice being made by the
particular embodiment being described. This location operates in
conjunction with the Retrieval Tool latching system and its purpose
will be explained later.
An upper hydraulic passageway, 19, is found at the saddle point of
the cupped tool face slightly below the bottom of the settling
slot. This passageway runs from the saddle point of the cupped tool
face to a `cut-a-way`, 9, located in the back of the whipstock. The
hydraulic passageway is threaded at both ends to accept a hydraulic
street-ell fitting. The `cut-a-way`, 9, extends from the hydraulic
passageway to the base of the whipstock below the hinge, 6. These
components operate ill conjunction with a hydraulic anchor packer
and serve to conduct hydraulic fluid from a running tool located on
the drill string to the hydraulic anchor packer when one is used
with the Whip-Anchor system. This subsystem will be explained
later.
The upper section of the whipstock, 4, is hinged to the whipstock
base, 5, via a hinge assembly, 6. The hinge assembly is shown in
detail in FIGS. 5A through 5C and is similar to a prior art hinge
except that springs, 95, have been added in spring openings, 83
through 86 and the hinge center is offset from the Whip-Anchor
center line by about 3/4 inch towards the tool face. These springs
sever to ensure that the whipstock will fall away from the point of
deviation against the back of the well bore. These springs are
similar to those found in `valve-lifters` used in engines. The
springs are retained in their compressed position while the
whipstock is being manipulated by a spring retainer shear pin, 88.
This pin is approximately 1/4 inch in diameter and runs through its
respective spring retainer shear pin opening in the upper section,
96, and base section, 97, of the whipstock. The upper section
opening, 96, and base section opening, 97, will only align when the
springs are compressed and when the whipstock is perpendicular to
its base. The spring retainer shear pin, 88, is held in place by
two snap rings, 93, in a snap ring groove, 94, at either end of the
pin within the base opening, 97. The technique for shearing this
pin, when the whipstock is set, will be explained later.
The upper and base sections of the whipstock are hinged together
using a hinge pin, 87, which passes through the hinge pin opening,
81, in the base, and through the corresponding hinge pin opening,
80 in the upper section of the whipstock. It should be noted that
the center of the hinge pin is offset towards the front of the
whipstock by about 3/4 inch; unlike the present art. This offset
assures that the spring retainer shear pin, 88, will shear
whenever; weight is applied in the downward direction on the
Whip-Anchor as it is set. Careful observation of FIG. 5B will show
that a large downward force will tend to push the upper section of
the whipstock backwards or away from the tool face. This is the
direction that the whipstock must fall (or move towards) in order
for proper hole deviation to occur. The downward force will pivot
about the off-set hinge, 87, shearing the spring retaining pin, 88.
This releases the hinge springs which will hold the back of the
whipstock against the well bore. The back of the hinge base, 89, is
sloped to assure that the upper hinge section 82, is not prohibited
from its backward motion while shearing the spring retainer shear
pin, 88. In a similar manner the top of the back of the hinge base,
90, is also sloped to avoid any chance of interference.
The spring force feature will find great utility in near vertical
holes (within .+-.5.degree. of vertical) and in holes where the
operator wishes to deviate from the low side of the well bore.
Deviation from the low side is seldom performed because of the high
failure rate that most operators have experienced.
The base section of the whipstock continues the `cut-a-way`, 9,
which is designed to hold a high pressure hydraulic line for use
with a hydraulic packer. The `cut-a-way`, 9, terminates in a
another hydraulic fluid passageway, 23. This passageway runs from
the cut-a-way a-way, 9, in the base section, through the center of
the base, and terminates in the bottom flange of the base where it
can communicate with a hydraulic packer, 14H, through a cross-over
sub, 15. The base hydraulic passageway, 23, has threads for a
street-ell connection where it enters the `cut-a-way`, 9. The
actual hydraulic plumbing will be explained later.
In the prior art of setting Whipstocks, it was generally accepted
that the OD or profile, 29, of the Whipstocks should have an
approximate clearance of, or slightly more than, one half inch
(1/2") within the well bore. It is possible in special situations,
well bore is in very "good condition", to reduce this clearance to
one quarter inch (1/4"). This invention has three sizes of
whipstock bodies to fit bore sizes from 33/4 inches to 121/2 inches
ID. Thus, for example, in a well bore using 60 PPF (pounds per
foot) casing having an ID of 121/2", the correct Whip-Anchor would
be the Type III, which has a body OD of 8". After the Whip-Anchor
was anchored (centered) in the 121/2'ID well bore, there would be a
21/4" clearance or gap between the 8" OD Whip-Anchor body and the
121/2" ID well bore. Depending on the degree of inclination in the
well bore to be sidetracked and the direction of the intended
sidetrack, an Optional Spacer, 8, may be required to reduce this
clearance (gap) to a minimum of 1/2" in the direction of the
intended sidetrack. This example is given for illustration only and
optional spacer requirements for given well bores can easily be
calculated using known art.
The drill string has a fulcrum effect created by the
milling/drilling tool and the watermelon mill(s) whenever it is
deflected (or deviated) to the "high side" of a well bore having
some degree of inclination from vertical. Thus, as the window
milling operation proceeds, the drill string acts as a lever to
force the window mill into the casing (or wall of an uncased hole)
under the guidance of the Deflector Head and subsequent travel
along the Tool Face of the Whip-Anchor body. Once the initial cut
into the side of the well bore has been made and once the mills
have moved along the Tool Face of the Whip-Anchor, they have formed
a "line of trajectory" equal to (or more than) the degree of slope
placed on the Tool Face of the Whip-Anchor. When the window mill
reaches the bottom of the Tool Face, it will have milled nearly all
the casing wall (or side of all uncased hole). The watermelon
mill(s) will still be on the Tool Face of the Whip-Anchor, giving
guidance and "fulcruming" the window mill away from the old well
bore.
In the instant invention, it may be necessary to use all optional
spacer at the base of the Whip-Anchor Tool Face whenever the gap
between the well bore and the Whip-Anchor body exceeds 1" and the
Whip-Anchor System is being used in a well bore with less than 10
degrees of inclination. The higher the degree of inclination from
vertical in a well bore, the more pronounced the "fulcrum effect"
and the spacer is not necessary. It might be noted, that as the top
of the Whip-Anchor rests against the 121/2" well bore, the
"trajectory path" created by the 8" OD Whip-Anchor Tool Face
increases from 3.18 degrees to 4.07 degrees. This increase in
deviation from the old well bore further enhances the movement of
the new path away from the old well bore. FIGS. 6A and 6B give
greater details on the optional spacer and its attachment to the
Whip-Anchor body to extend the Tool Face and lessen the gap. (In
general, all illustrations of the Whip-Anchor system which use a
hydraulic packer are shown with this optional spacer; see for
example FIG. 2.) In designing this Whip-Anchor system, the bottom
or base, 25, of the setting slot should be located above the
fulcrum point for the watermelon mills. If this is not done, then
special watermelon mills must be used which do not bit into the
setting slot when in use.
The optional spacer, 8, is attached to the lower portion of the
upper section of the Whip-Anchor by two (or more if required)
studs, 74. The tool face side of the spacer, 72, is a continuation
of the Whip-Anchor Tool Face, 11. As a consequence, the tool face
of the optional spacer will have the same slope and cupping as the
type (size) Whip-Anchor body to which it is attached. The two
studs, 74 pass through apertures in the optional spacer, 75, and
into threaded openings, 68 which are in the Whip-Anchor body. The
back of the spacer has the same curvature as the body OD of the
type of Whip-Anchor to which it is being attached. The width of the
optional spacer, 79, will be the same as the width of the upper
section of the Whip-Anchor and the length of the spacer, 78, will
be set by the Whip-Anchor type (size). The optional spacer depth,
77, and the spacer base length, 76, will be set by parameters to be
determined by the Whip-Anchor type (size) and bore hole
diameter.
The table below gives approximate dimensions for commonly used well
bores and conditions. The table is not intended to serve as a
limitation on this disclosure but is offered only as illustration
and guidance for those skilled in the art. Remember that a spacer
is not generally necessary and the optional spacer will find its
greatest use whenever the well bore is within 10 degrees of
vertical and when the gap between the centered (set) whipstock body
and the well bore exceeds about one inch.
The base of the whipstock, 5, is attached to a cross-over sub, 15,
which in turn is attached to a mechanical packer, 14M. The packer
that is shown in FIG. 1 is a very old style called a "set-down"
packer. This packer is shown for illustration and ease of
explanation only and is not considered to be a limitation on the
invention. This invention is designed to be used with any style of
mechanical (or hydraulic) anchor packer.
TABLE 4 ______________________________________ OPTIONAL SPACER
PARAMETERS Tool Face Whipstock Bore Size Spacer Curve and Type Size
Casing Size Depth Back Cup Slope
______________________________________ I 31/2 41/2-65/8 33/4-41/2 0
NA NA at NA I 31/2 41/2-65/8 43/4-51/2 1/2 31/2 51/2 at 2.09 II
51/2 7-85/8 53/4-7 0 NA NA at NA II 51/2 7-85/8 71/4-8 5/8 1/2 8 at
2.62 III 8 95/8-133/8 81/4-10 0 NA NA at NA III 8 95/8-133/8 10-11
1 8 121/2 at 3.18 III 8 95/8-133/8 111/2-121/2 13/4 8 121/2 at 3.18
______________________________________
The instant invention can readily be adapted for use with a
hydraulic packer as shown in FIG. 2. The exact same whipstock is
used except for additional plumbing features. A hydraulic
street-ell, 20, is screwed into the matching threads within the
upper hydraulic passageway, 19, in tire face of tire whipstock. In
a similar manner another hydraulic street-ell, 21, is screwed into
tire backside entry of tire same upper hydraulic passageway, 19.
Finally a further hydraulic street-ell, 22, is screwed into the
base hydraulic passageway. A high pressure hydraulic hose, 24, is
attached between the two street-ells located in the `cut-away`, 9,
in the backside of tire whipstock. Standard hydraulic packer
procedures are now followed. A cross-over sub, 15, is screwed onto
the whipstock followed by a hydraulic packer, 14H. A hydraulic
connection is made between the face street-ell, 20, and tire
setting tool. This part of the invention and procedure will be
explained later.
Thus, one model of Whip-Anchor System using three sizes of
whipstock body can serve as a whipstock/packer assembly in well
bores from 31/2 inches to 121/2 inches and the same one model can
be used with mechanical of hydraulic packers. As will be explained
in a latter part of the discussion, this Whip-Anchor is
retrievable.
Attention should now be directed to the Setting Tool illustrated in
FIGS. 7 through 10. It should be remembered that the same setting
tool will operate a mechanical or hydraulic packer used in
conjunction with the instant invention. The general setting tool
will be described first and then the necessary changes that make it
a mechanical or hydraulic Whip-Anchor setting tool will be
described. There are three different sizes of setting tool because
there are three different sizes (or types) of Whip-Anchor. The
setting slot, 12, is determined by strength of material and
requires set by the size of the tool and the pull that will be
required to retrieve the tool. Thus, the slot width varies from
about 1 inch for the Type I tool, to about 11/2 inches for the Type
II tool, and to about 2 inches for the Type III tool. It should be
noted that other sizes of Whip-Anchor could be used and the setting
slot width will still be determined by similar strength of material
consideration: thus, this example width should not be construed as
a limitation on the instant invention. In a similar manner the
length of the tool, 109, as measured from the sub, 100, to the
bottom face of the setting tool, 108, will vary with the
Whip-Anchor type.
The setting tool, 2, consists of three subassemblies, which are
best illustrated in FIG. 7 or 8, these being:
the setting tool rectangular bar, 101:
the setting tool fluid line or tubular, 102; and
the setting tool sub, 100, often called the top sub.
The rectangular bar fits within the setting tool slot, 13, located
in the face of the whipstock as previously discussed. In the
preferred embodiment of the setting tool the fluid line or tubular,
102, is threaded into the top sub as shown in FIG. 10A. The threads
can be back welded if desired. The fluid line or tubular is capable
of safely carrying circulation mud or hydraulic fluid under
pressure. The bar is welded to the setting tool fluid line or
tubular, 102, and in turn to the top sub, 100, which is capable of
connection to the drill string. It is possible to weld the tubular
directly into a recess in the top sub without using threaded
fittings; however, threaded fittings would make construction of the
setting tool easier. FIG. 9A illustrates a cross-sectional view of
the setting tool, 2, within the setting slot, 13.
The pertinent details of the setting tool will be discussed. Turn
now to FIG. 9, which shows a close up view of the tool in the
setting slot and at the base of the setting slot and to FIGS. 10A
through 10D, which show construction of the tool. The bottom face
of the setting tool, 108, has a slight angle, 106, which means that
the setting tool bottom rests on the setting slot bottom of the
whipstock at the point farthest away from the tool face. There will
be a slight gap between the setting tool bottom face, 108, and the
setting slot bottom, 25, nearest the whipstock tool face, 11. This
gap is on the order of several thousandths of an inch and its
purpose will be described later. The setting fluid line or tubular,
102, terminates at a point slightly below the termination of the
bar. The actual distance is not critical because it is used to
allow for ease of attachment of a hydraulic fitting. The inside of
the open end, 107, of the fluid line is threaded to accept a
hydraulic fitting. The setting tool is attached to the Whip-Anchor
by a shear pin, 39. This shear pin is the same as used in the art
for currently setting whipstocks: however, it is scored to assure
perfect fracture.
The shear pin, 39, is made of mild steel and is threaded to fit the
threaded aperture, 105, in the setting tool. The shear pin passes
through a corresponding aperture, 62, in the whipstock. This
opening is larger than the shear pin and allows for slight movement
of the shear pin within that opening. This is to give the shear pin
some relaxation from any applied downward or torsional forces
exerted by the Setting Tool in reaction to forces applied to the
drill string. This allows the downward force to be applied directly
to the bottom of the setting slot and the torsional forces to be
directly applied to the side walls of the setting slot.
Additionally, this loose fit of the shear pin, 39, in the whipstock
aperture, 62, ensures that if sufficient downward force is applied
on the setting tool, then the bottom face of the setting tool will
fully set down on the bottom of the setting slot. This action will
impart a shear force to the spring retaining shear pin, 88, because
of the combination of the offset hinge, 6, and the bottom tool face
angle, 106, on the setting tool.
It should be noted that if the spring retainer pin, 88, is sheared
while the Whip-Anchor is being run into the well bore, the hinge
section of the instant invention reverts back to the prior art
employed by current whipstock/packer systems using an unpinned
hinge. This condition, which could be brought about by having to
force the whipstock through a particularly tortuous path and having
to exert a great amount of downward force on the setting tool, does
not cause any problems in using the instant device. This is because
the base of the anchor packer has a larger OD than the slips
(wedges or scaling) elements section of the packer and further more
is "bullet shaped." (See FIG. 3) The instant invention will operate
better than the prior art in a tortuous path for two reasons:
a) a great amount of downward force (of weight) can be applied
without any fear of shearing the shear pill because the force is
applied directly to the Whip-Anchor via the setting tool sitting in
the bottom of the setting slot, and
b) because the Whip-Anchor can be rotated without fear of shearing
the shear pin due because the torsional force (rotation) is applied
directly to the walls of the setting slot.
Additionally the shear pin has a groove, 38, cut axially around the
pin at such a location so that when the pin is installed the groove
is located slightly inside the setting slot face. This groove
assures that the shear pin will shear at the groove. This means
that, once the pin has sheared, there will be no material extending
from the whipstock shear pin aperture, 62, into the setting slot.
The back of the whipstock has a recess, 63, which accepts the Allen
Cap Head of the shear pin and assures that no material extends
beyond the back side of the whipstock.
TABLE 5 ______________________________________ SHEAR STUD PLACEMENT
AND SETTING SLOT BASE PARAMETERS Up from Whip-Stock Stud Slot Slot
Slot base Stud Size Size Width Depth Length of Slot Depth
______________________________________ I 1/2" 11/32" 0.81" 221/4"
1" 3/8" II 5/8" 117/32" 0.90" 191/2" 11/4" 1/2" III 3/4 21/32"
1.00" 18" 11/2 3/4" ______________________________________
The recess, 63, has an axial groove, 64, which can accept a keeper
ring, 37, which will keep the Allen Cap Head within the body of the
Whip-Anchor after it is sheared. Any type of retainer mechanism,
such as welding could be employed. The table given above is for
purposes of illustration of the best mode. It should not be
construed as a limitation. All dimensions will be set by strength
of material considerations; thus, if the material changes, or if a
weakness shows tip, a metallurgical engineer would know how to
adjust the values given above.
When the setting tool, 2, is used with a mechanical packer, the
setting tool fluid line, 102, is left open as shown in FIG. 7. Mud
can be circulated through this fluid line and if an MWD tool is
attached to the setting tool sub, proper Whip-Anchor tool face
orientation may be accomplished. If the operator requires, the
fluid line, 102, can be attached to circulate through a mechanical
anchor-packer with a check valve to be able to wash to bottom in
open (uncased) hole conditions. (This arrangement is not shown and
would not impair the operation of the Whip-Anchor. The arrangement
would use all of the described hydraulic anchor packing plumbing
and the mud would circulate in the same path down through the
cross-over sub and out of the bottom of the mechanical packer.)
FIG. 8 shows the arrangement of the setting tool when it is used to
set a hydraulic packer. If the setting tool is used with a
hydraulic packer, then a hydraulic hose, 113S, would be attached to
tubing at the threaded open end, 107, and run to the equivalent
hydraulic fitting, 20, on the cupped face of the Whip-Anchor. The
procedures (or methods) for using this setting tool with either the
hydraulic or mechanical packer will be discussed later. It should
be noted that the Whip-Anchor is illustrated in FIG. 8 as being
connected to a larger packer via the cross-over sub, 15. The
optional spacer, 8, is also shown; however, the hydraulic fittings
and hose within the whipstock have been omitted for clarity.
Additional illustrations may be found in FIGS. 16 through 19.
An alternate embodiment of the setting tool is shown in FIG. 10C
and 10D. In this embodiment, the steel fluid line or tubular, 102,
has been replaced with a high pressure hydraulic hose, 113L, which
runs directly from the threaded tubular recess, 112, on the top
sub, 100, to the street-ell fitting, 20, on the Whip-Anchor tool
face. This hose would be held in place by stainless steel clamps,
114, and screws (not shown) screwed into the setting bar as needed.
In fact, as previously mentioned, the same hydraulic fluid lines
can be used in conjunction with a mechanical packer to wash the
bottom of the hole with drilling mud in open hole (uncased)
conditions, otherwise, when using a mechanical packer, either
variant of the hydraulic hose, 113, would be omitted.
A table giving approximate dimensions for the three tools is given
below. These dimensions should not be construed as a limitation on
the invention, nor should the fact that only three sizes are given
be similarly construed, for the reasons given earlier in this
discussion of the invention. The table is for illustration only and
allows a person skilled in art of whipstocks to choose the proper
tool(s) for the proper application.
TABLE 6
__________________________________________________________________________
ADDITIONAL SETTING TOOL PARAMETERS Whipstock Type Bar Tool Fluid
Line Top Sub OD Shear Stud or Size Length, Width, Depth Size -
Rating & Connection Size
__________________________________________________________________________
I - 31/2" OD 40" .times. 1" .times. 1" 4000 PSI 5/8" 33/8" w/23/8"
IFB 1/2" II - 51/2" OD 40" .times. 11/2" .times. 11/4" 4000 PSI
43/4" w/31/2" IFB 5/8" III - 8" OD 40" .times. 2" .times. 11/2"
4000 PSI 61/4" w/41/2" IFB 3/4"
__________________________________________________________________________
The retrieval tool for the Whip-Anchor is designed to engage a
retrieval slot located in the upper portion of the whipstock within
the setting slot. FIGS. 11A-B and 12A-D show the particulars needed
to understand the device. The preferred embodiment for the
retrieval tool is shown in FIG. 12A, with a cross-section in FIG.
12AA. The preferred embodiment uses a hydraulic hose to pass fluid
to the wash port, located in the face of the hook in the retrieval
tool. The alternate embodiment is shown in FIG. 12B, with a
cross-section shown in FIG. 12BB. The alternate uses a welded
tubular in place of the hydraulic hose, which will increase the
strength of the tool and will be the most useful for Type III
Whip-Anchors. Ally retrieval tool must not exceed the diameter of
the Whip-Anchor body (bore), and the tool must be able to withstand
three times the force required to release the anchor-packer at the
base of the Whip-Anchor.
The preferred embodiment will find greatest use with Type I and
Type II Whip-Anchors because the ID of the bore hole limits the
size of the Retrieval Tool. Turning then to FIG. 12A, the Retrieval
Tool simply consists of a tool joint, 180, a bar, 178, and a
specially shaped hook, 177. Although the hook could be welded to
the bar, it is much better to manufacture the hook and bar as a
unit because of the tremendous forces or weight that the Retrieval
Tool will have to endure in releasing the anchor packer (not
shown). The tool joint, 180, can have a threaded fitting or a weld
fitting for attachment to other Bottom Hole Assembly (BHA) tools,
such as the piston sleeve valve assembly or sub, 140, shown in FIG.
12C and which will be discussed shortly. The tool joint is attached
to the Retrieval Tool bar, 178, and to the hook, 177, either during
manufacture of the Retrieval Tool as a complete unit or by welding
the bar to the tool joint. (The preference is for a complete
integral unit due to, again, the tremendous forces that will
present.) There is a recess, 179, whose depth, 168, is set by the
type of Whip-Anchor being used. The recess permits the Retrieval
Tool to centralize itself in the setting slot, 13, of the
Whip-Anchor, thus, the depth, 168, will vast with tool type. The
retrieval tool latching mechanism, 28, is located on the face of
the bar (at location 27) that will engage the retrieval slot. This
mechanism and its embodiments will be discussed later.
The hook, 177, has a wash port, 175, located in its face. The wash
port, 175, connects directly to a wash passageway, 176, which is
cut through the center of the hook, through the bar, and terminates
in a threaded outlet at the back (opposite the tool face) of the
bar. A hydraulic street-ell, 185, is fitted in this back opening of
the wash passage and a hydraulic hose, 183, runs from the
street-ell to a threaded port, 182, in the tool joint. The threaded
port, 182, connects to the inside of the tool joint via a fluid
passageway, 181. Tile hydraulic hose, 183, is strapped to the back
of the bar, 178, by stainless steel clamps, 184, which are in turn,
attached to the bar, 178, by stainless steel screws (not shown). An
additional piece of metal, 190, is welded to the back of the bar,
by weld, 205, to protect the street-ell, 185. It would be possible
to form the protector plate, 190, as a part of the complete
Retrieval Tool, while manufacturing the bar/hook/tool joint.
The wash port, 175, is designed to swab the well bore and the
setting/retrieval slots, 12 and 13, as the retrieval tool is making
its trip into the well bore. It is realized that during regular
drilling operations, involving a deviated hole, cuttings (formation
chips) will settle in all crevices within the Whip-Anchor. Thus,
the setting slot, 13, which acts as a guide for the Retrieval Tool
hook, as well as the actual retrieval slot, could become filled
with cuttings. High pressure mud flow will wash those cuttings free
of these critical slots.
The Retrieval Tool hook is carefully shaped to accomplish several
ends. Viewed from the bottom, as in FIG. 12AA, the front of the
hook is slightly narrower, 165, than the body of the hook, which
has the same width, 166, as the Retrieval Tool bar, 178.
Furthermore, when viewed end on as in FIG. 12D, it can be seen that
the width of the top of the hook, 164, is slightly narrower than
the width of the front of the bottom of the hook, 165, which widens
to the width of the bar, 166. The Retrieval Tool hook is set at an
angle of 35 degrees to the Retrieval Tool bar and all leading edges
are rounded for ease of engagement into the retrieval slot, 12. All
dimensions of the Retrieval Tool hook, bar, setting slot and
retrieval slot are set by strength of material considerations and a
representative set is given in table 7 below. There must be
sufficient strength for the hook to on pull the Whip-Anchor and
break the lower anchor packer loose, plus be able to pull the
Whip-Anchor assembly from the hole without material failure. Thus,
these dimensions change with the size of the Whip-Anchor. The
tables of dimensions give best mode dimensions for accomplishing
this purpose; however, with the use of different steels, the
dimensions could change and are readily calculated by metallurgical
engineers. A suggested set of parameters is given in the table
below: these parameters are suggestions only and can easily vary,
with the material of construction.
TABLE 7
__________________________________________________________________________
RETRIEVAL TOOL DIMENSIONS Whip-Anchor Tool Tool Hook Hook Hook Wash
Material Top Latch Hook Size Length Width Depth Width Length Port
ID Strength Connection OD Angle
__________________________________________________________________________
I 54" 31/2" 1" 1" .times. 1/2" 4" 1/4" 100K 23/8" IFB 1/4"
35.degree. II 56" 51/2" 11/2" 11/2" .times. 1" 5" 3/8" 120K 31/2"
IFB 3/8" 35.degree. III 58" 71/2" 2" 2" .times. 11/2" 6" 1/2" 160K
41/2" IFB 1/2" 35.degree.
__________________________________________________________________________
FIG. 11C shows the Retrieval Tool hook fully engaged within the
retrieval slot 12, The distance, 172, between the base of the
setting slot, 25, and the bottom opening of the retrieval tool is
set by strength of material considerations. This length also
contains the shear pin aperture, 62, which is NOT shown in the
figure. The 35 degree angle for both the retrieval slot and the
Retrieval Tool hook is designed to allow the hook to slide
backwards and away from the retrieval slot whenever the operator
"slacks off" on the weight. This means that the hook can be
disengaged if the Whip-Anchor becomes stuck in the bore.
It is important that the hook remains engaged until the operator
truly wishes disengagement. For example, if there is a set of
fishing jars in the BHA, and the operator wishes to use them, they
must be reset each time after use. Fishing jars are reset by
slacking off and allow the drill string weight "cock" the jars.
Thus, disengagement of the hook must be controlled so that fishing
jars can be reset. This can readily be accomplished by the
Retrieval Tool latching mechanism, 28, whose approximate location
is shown at 27. The latching mechanism consists of a spring loaded
shear pin and corresponding opening for the pin to pop into
whenever the retrieval tool is fully engaged in the retrieval slot.
There are two embodiments for the device.
The preferred embodiment for the Retrieval Tool latching mechanism
is shown in FIG. 14A, in which the latch pin, 206, and spring, 207,
are retained by a keeper, 208, in an aperture, 209, within the
setting slot face of the Whip-Anchor. This position is preferred as
best mode because of strength of material considerations. The latch
pin, 206, strikes within a corresponding opening. 210, in the
Retrieval Tool face. The opening, 210, is larger than the diameter
of the pin to ensure engagement. The diameter of the pin (and the
corresponding opening) is set by the reset weight requirement of
the fishing jars. This latching pin will shear if sufficient weight
is applied to the pin: however, the pin is designed to bear the
weight of reset for the fishing jars; thus, disengagement is
controlled. The operator can reciprocate the Whip-Anchor; he can
reset his fishing jars and he can rotate it without fear of
inadvertent disengagement of the Retrieval Tool hook; but, when the
tool is completely stuck, the operator can disengage by slacking
off hard on the tool, shearing the latch pin, and falling out of
the retrieval slot. The operator would rotate the Retrieval Tool by
at a quarter turn and trip out of hole. The alternate embodiment of
the retrieval latch mechanism, shown in FIG. 14B, is the reverse of
the first: however, this is not best mode because the opening for
the mechanism, 211, would weaken the Retrieval Tool bar.
An alternate embodiment of the basic Retrieval Tool is shown in
FIG. 12B. This embodiment, as previously explained, will work best
with the larger Whip-Anchor Types due to the ID of smaller well
bores. The Retrieval Tool consists of the same tool joint, 180,
Retrieval Tool bar, 178, and hook, 177, as with the preferred
embodiment and all the features are similar. The difference is in
the use of a tubular, 187, which is welded to the bar, 178, to
conduct fluid to the hook wash port, 175 rather then a hydraulic
hose. The tool joint has a fluid passage, 181, which terminates in
a weld fitting, 186, in which the tubular, 187, is welded. (It
would be possible to use a threaded fitting anti back weld the
threads if desired.) The tubular is then welded to the back of the
Retrieval Tool bar, 178, along the joint, 188, between the two
parts. The hook fluid passage, 176, from the wash port is extended
into the tubular and the tubular is sealed by a cap or plug, 189.
All other details are the same as with the preferred
embodiment--hook dimensions, bar dimensions, etc., which are set by
strength requirements.
FIGS. 15A through 15D show the Retrieval Tool hook approaching the
Whip-Anchor, rotation or alignment with the setting slot and
engagement. As explained later in this discussion, the Retrieval
Tool with the proper BHA running tools would be tripped into the
hole and the Retrieval Tool face alignment would be checked when
the tool is near the Whip-Anchor, the drill string rotated (as in
FIG. 15B) to align the tool with the setting slot, and further
lowered. The setting slot would provide guidance to the Retrieval
Tool hook face. The hook would bottom out on the bottom of the
setting slot bottom or base, 25. This condition can be observed by
a decrease in travelling block load or drill string weight. The
string would be pulled upward and the Retrieval Tool hook should
engage the retrieval slot. Engagement should be noted by an
increase in drill string weight. However, often when pulling a
drill sting upward over short distances, the string will jam in the
well bore and frictional effects would give higher weight
indications: thus, it is possible that a false indication of hook
engagement could be observed, ed at the surface. There is a
secondary method to indicate proper hook engagement which sends a
mud pressure pulse to the surface.
The inventor proposes several different embodiments for sending a
mud pressure pulse to the surface. The preferred apparatus for
determining hook latch in the retrieval slot may be found in a
"piston sleeve valve" which is designed to shut off mud flow when a
`hook load` is applied to the piston sleeve valve. Simply stated a
sub containing the piston sleeve valve is attached to the tool
joint, 180, and is placed in the BHA immediately above the
Retrieval Tool such that whenever weight is `picked up` by the
Retrieval Tool hook, the piston sleeve valve closes and sends a
pressure pulse to the surface.
FIG. 12C illustrates a piston sleeve valve, 140, but does not show
the Retrieval Tool subassembly which would contain the only
retrieval tool bar and hook as shown in FIG. 12A or FIG. 12B. The
piston sleeve valve starts with a tool joint, 141, in which an
upper fluid passageway, 142, has been machined to intersect a
cross-passageway, 139. The cross-passageway terminates on the side
of the tool joint in a threaded opening in which a hydraulic
street-ell, 143U, is placed. A hydraulic line (or hose), 144,
extends from the upper street-ell to a lower street-ell, 143L. The
lower street-ell conducts fluid into the piston chamber, 156, which
is machined in the lower section, 160. The lower section of the
piston sleeve valve is screwed to the tool joint by buttress
threads, 145. The fact that the piston sleeve valve can be opened
allows section of the internal parts.
The piston valve, 146, resides within the lower section, 160, and
its associated piston chamber, 156. The piston valve, 146, has a
piston valve head, 154, which is larger then the piston valve and
is capable of supporting the hook load transferred by the Retrieval
Tool hook whenever the Whip-Anchor is latched and pulled. A spring,
148, is generally placed between the piston head and the bottom of
the piston chamber which helps to support the piston valve up
against the tool joint, 141. The piston valve, 146, has a set of
piston rings, 147, which will seal the piston valve at area, 159,
immediately below the piston chamber, 156. There is a central fluid
passageway, 157, in communication with a cross fluid passage, 158,
within the piston valve. Fluid flow may occur between the lower
street-ell and the piston passageways via the upper piston chamber
and around the piston spring, 148.
Normal fluid flow, 150, would enter the top of the tool at the tool
joint passage, 142, and follows the path shown by the heavy arrows
through the hydraulic hose and the associated street-ells, into the
piston chamber, through the piston passageways and out of the
bottom of the tool. The force of the fluid acts against the piston
head and holds the head (along with some help from the optional
spring) up against the tool joint. When a hook load is transferred
to the tool, the piston extension, 149, will transfer the load to
the piston, 146, and onto the piston head, 154; thus, compressing
the piston spring, if installed, and overcoming the force exerted
by the fluid. This will draw the piston across passage below the
entry point of fluid at the lower street-ell, 143, thus, shutting
off fluid flow to the lower portion of the piston and onto the
Retrieval Tool. The closure of the access port will, of course,
send a pressure pulse to the surface which is an indication of
Retrieval Tool hook engagement on the Whip-Anchor. Although the
piston extension, 149, has been shown as having circular
cross-section, the extension must not rotate within the assembly. A
simple index should be added to the extension to pass within a
key-way or even a short length of kelly-pipe (hex-pipe) with the
housing machined to accept the kelly-pipe can be used.
Although the piston sleeve valve has been described in conjunction
with the retrieval tool, the device can be used in any fishing
operation in which drilling fluid is circulated. For example, in
wireline fishing operations, it is very difficult to know when the
fishing tool has engaged the broken wireline. Normally, the driller
lowers the wireline fishing tool into the wellbore, while rotating
the drill string. The string is point a point where the broken line
is expected; an attempt to pick tip the line is made; and, the
drill string is tripped back to the surface. If nothing is
captured, the operation is repeated, except the drill string is run
to a lower point in the wellbore.
A major problem will occur if the drill string entangles the broken
wire line for any distance above the fishing tool. This
entanglement will cause the drill string to stick in the wellbore
and it can become impossible to trip the drill string out of the
wellbore. A wireline device is extremely light, so that normal
drill string weight indicators will not measure any increase in
weight whenever a broken wireline is captured by the fishing tool.
The piston sleeve valve can be set to indicate capture of the
wireline by sending a pressure pulse up the drill string in the
circulating mud. Now it should be noted that the piston sleeve
valve will actually cut off circulation; however, a similar drill
string arrangement may be used as shown in FIG. 20 where the piston
sub, 100, is replaced by the Piston Sleeve valve. The
pinned-by-pass valve, 127, will allow for continued mud
circulation. It is possible to design the openings within the
piston sleeve valve so that the circulation is only partially cut
off; thus, producing a pressure pulse at the surface while
maintaining circulation.
It is possible to increase the circulation pressure at the surface
and attempt to force the piston head back up into the tool joint.
Thus, complete latching of the Whip-Anchor System, wellbore
deviation assembly, broken wireline, or other device can be tested
for by increasing mud pressure and seeing if the flow increases. If
an increase in pressure does not significantly increase the mud
flow, then hook engagement has occurred.
There are two alternate devices which are capable of producing a
pressure pulse at the surface and these are shown in FIGS. 13A and
13B. FIG. 13A shows the preferred embodiment for a Retrieval Tool
incorporating a hydraulic pressure hose, 183, to bring fluid to the
wash port, 175. This technique will work equally well with the
alternative method of applying fluid to the wash port which uses
the welded tubular (not shown in FIG. 12B). The mud pressure pulse
is produced by stopping the wash port fluid at the wash port, 175,
through the use of a valve, 203, located in the hook, 177. The hook
valve, 203, is operated by a loaded stem actuator, 204, which
protrudes from the top of the hook. When the hook properly engages,
the retrieval slot at the top of the slot will squeeze on the
actuator, 204, thus, closing the hook valve and sending a mud
pressure pulse to the surface. An alternate embodiment is shown in
FIG. 13B which uses an internal flapper valve, 201, actuated by a
control rod, 202.
The second alternate embodiment uses a full body tubular Retrieval
Tool with a hook. The Retrieval Tool is made in several parts. A
standard tool joint, 191, is welded to tubular section, 192, which
terminates in a threaded connection, 194. A second tubular section,
187, is welded to a Retrieval Tool hook, 177, has a rounded bottom
end, 198, and matches the first tubular, 192, at the threaded
connection, 194. The second tubular section, or Retrieval Tool
tubular, 187, contains a flapper valve sleeve. 195, which restrains
and holds the flapper valve, 201. The sleeve provides a slightly
offset passage for the fluid, 196, and stops the fluid from getting
behind the flapper valve and closing it inadvertently. The sleeve
passage, 196, continues through a smaller passage, 197, and joins
the wash port passage, 176, which terminates in the wash port, 175.
All other details, hook dimensions, lengths, etc. are similar to
the preferred embodiment. When the Retrieval Tool hook engages the
retrieval slot, the hook is naturally pulled towards the setting
slot, which presses against the flapper valve actuator, 202, thus,
closing the flapper valve, 201, producing a pressure pulse at the
surface.
A final alternate embodiment for the setting tool is illustrated in
FIG. 32. In this embodiment, the base of the setting tool is
extended into the body of the Whip-Anchor. This enlarged base would
permit greater downward force to be exerted on the Whip-Anchor.
This alternate would compromise the integrity of the Whip-Anchor if
it is to be retrieved, for it would be weakened.
The use of the Whip-Anchor does not differ greatly from the prior
art; however, this tool simplifies the procedure, actually reduces
a step, provides methods whereby only one type of tool need be kept
in warehouse stock, provides a whipstock that can be set in
tortuous well bore conditions, provides a retrievable whipstock,
and provides a tool which permits bottom hole washing in open hole
conditions with a mechanical packer, just to name a few of the
myriad differences in the apparatus and method of using the present
invention. In keeping with the spirit of the previous discussion,
the simplest operation will be described initially and the
differences between the use of the mechanical anchor packer and the
hydraulic packer will be discussed. The various embodiments and how
they affect the operator will also be considered.
Reference will be made to FIGS. 15 through 29. Normal drill floor
procedures for assembling the Whip-Anchor and choosing the proper
combination of downhole running tools is almost the same as with
the prior art and it makes little difference, as far as this
general discussion is concerned, the Type (size) of Whip-Anchor for
a given size bore or whether the well bore is open or cased. Those
skilled in the art of setting whipstocks will be able to supply
minor missing details and see the minor differences that would
occur between cased and uncased holes. The real differences between
the instant invention and the prior art will be discussed.
Assume that the operator has made the decision to deviate a well
bore, that the operator has properly surveyed the well bore, that
the collar locator run has been made, that the operator knows the
hole conditions and, that the operator has made the proper trip
with a locked up bottom hole assembly, thus, preparing the hole for
setting a whipstock. Assume further, that the hole is cased and
that the operator has decided to use a mechanical packer, which is
the simplest method to describe. This discussion will also assume
that the operator will take advantage of the instant invention in
that it allows the use of MWD (Measurement While Drilling) and that
the operator has chosen to use an MWD tool to orientate the face of
the Whip-Anchor.
The Whip-Anchor would normally be brought to the drill floor in an
assembled condition. That is, the Whip-Anchor service
representative would assemble the tool. Proper choice would be made
for the deflector head which would be mounted per the previous
discussion. Proper choice would be made for the anchor packer size
and that would be mounted to the base of the whipstock using the
proper cross-over sub. If the optional spacer is required, then
that would be mounted. In other words the tool would look some what
like FIG. 1, or FIG. 2, and/or FIG. 3. The assembled Whip-Anchor
would be set at the rig staging area while all preliminary),
procedures (standard) would be undertaken.
The running assembly, that is the tools which will be attached
between the setting tool and the drill string, should be assembled
before placing the Whip-Anchor on the rig floor. Normally a single
section (or joint) of Heavy Weight Drill Pipe, 122, is picked up
with the drill pipe elevators and used as a "handling sub" because
of the ease in attaching the tools below it. Any cross-over sub,
orientating sub, by-pass valve, piston sub and setting tool, that
are required, would be attached to the single joint of heavy weight
drill pipe and made up to their proper torque with the rig tongs at
this time. FIG. 20 shows an assembly for the assumed conditions
given above. These tools are the setting tool, 100, a cross-over
sub, 131, if necessary, and MWD tool, 127, or an optional
orientation sub (not shown), a single joint of heavy weight drill
pipe, 122, and required collars, 121, for attachment onto the drill
string, 120. These assembled tools would be stored in the elevators
out of the rotary table working area (above or to one side) because
the travelling block with drill pipe elevators is not needed in
handling the Whip-Anchor assembly.
The Whip-Anchor assembly would be picked up with an "air hoist" or
the "cat line" and landed in the rotary table. It is then secured
with appropriate slips and clamps. The aforesaid assembled tools
would be brought into position, via traveling block and elevators,
and the setting tool, 100, would be attached to the Whip-Anchor,
using the shear stud, 39. The shear pin keeper ring, 37, should be
placed in its proper position on the Whip-Anchor to make certain
that the sheared head does not interfere with the operation of the
Whip-Anchor. After orientation of the Whip-Anchor tool face to a
"mark" on the tool joint of the heavy weight drill pipe because the
MWD tool is to be used for orientation, the "blind rams" on the
Blow Out Preventer (BOP) system would be opened, if closed, and the
total assembled tools would be landed in the rotary table with the
tool joint of the heavy weight drill pipe at "working height".
Because an MWD tool is to be used, it would be picked up with the
drill pipe elevators and traveling block, and aligned with the
"mark" on the tool joint of the heavy weight drill pipe.
It might be noted here, that some operators like to run an
orientating sub (not shown) above the MWD in case of MWD failure or
simply because they want to check the orientation with two
different survey instruments: hence, the choice of a wire line
device. Also in the prior art, the joint of heavy weight pipe was
required to give the needed "fulcrum effect" for the Starter Mill,
which was attached to the whipstock, to make the 20 inch (.+-.)
starting cut. In the instant invention, although no longer needed
in the Whip-Anchor setting run, the joint of heavy weight drill
pipe would still be very helpful in picking up and laying down the
tools that are used directly above the Whip-Anchor.
It is important to note that with the simplest embodiment it does
not matter which embodiment of setting tool is in use. In the
preferred embodiment, the opening, 107, in the tubular, 102, is
left open. In the alternate embodiment, the threaded opening, 112,
is left open.
Now suppose that the operator wished to use this invention to its
full potential and wash the hole bottom through the mechanical
packer. Before the Whip-Anchor would be lowered into the hole, a
high pressure hydraulic hose must be connected between the setting
tool and the hydraulic fitting on the Whip-Anchor tool face. It is
assumed that the Whip-Anchor service representative has installed
the internal plumbing in the Whip-Anchor: namely the extra
street-ells, 20, 21, and 22 plus the `cut-a-way` hydraulic line.
The internal plumbing is identical to the plumbing required for a
Hydraulic packer. The difference in setting tool embodiments is not
much for in the preferred embodiment, a short hydraulic hose, 113S,
should be attached between the tubular opening, 107, (via the
required hydraulic fitting, 110) to the tool face street-ell, 20,
before the Whip-Anchor is lowered into the hole. In the case of the
alternate embodiment, a long hydraulic hose, 113L, is attached to
threaded recess, 112, and onto the Whip-Anchor tool face
street-ell, 20. (Note there is really no difference between this
procedure and the procedure required with a hydraulic packer-the
only difference is in the type of fluid passing through the
plumbing.)
A suggested bottom hole tool assembly for a hydraulic packer is
shown in FIG. 21 where the operator chooses to use only a wire line
survey for orientation of his Whip-Anchor face. These tools are,
the setting tool, 100, a piston sub, 130, a short sub 129, an
orientation sub, 126, any required cross-over, 124, followed by the
single joint "handling sub", 122. An alternate assembly is shown in
FIG. 22 where the operator chooses to use an MWD tool for
Whip-Anchor orientation, if an orientation sub were required it
would be placed above the MWD tool. The order of the tools is
somewhat critical for the pinned by-pass sub, 128, must be placed
below the MWD, 127, and above the short sub, 129. The assembly
techniques for these tools is similar to that described above and
it is known that the short sub, 129, is initially made up `chain
tight` until after hydraulic fluid is placed in the piston sub.
An illustration of a piston sub, 130, which would fit a Type It
Whip-Anchor, is shown in FIG. 29. This concept is in relatively
common use, but it will be described here because this particular
tool serves two functions and will greatly enhance the Whip-Anchor
setting process; hence, the use of this tool forms a part of the
preferred method of setting the tool.
These two functions are:
1) the sub provides isolation between the drill mud fluid and the
required clean hydraulic fluid needed to set a hydraulic packer,
and
2) the sub provides a simple way for mud to drain from the drill
string as it is withdrawn from the bore hole after setting the
Whip-Anchor; thus, avoiding the spray of mud on the rig floor when
each stand is broken.
The Whip-Anchor will most likely be used in old bore holes and,
usually, all oil based drilling mud, which is considered toxic by
the regulating authorities, is used. Thus, when pulling out of the
hole, it is imperative that the amount of fluid spray coming from a
"breaking" tool joint be reduced. This piston sub will accomplish
that purpose and is much better than most similar tools currently
supplied by major suppliers of whipstocks.
FIGS. 29 and 30A-B, are illustrations of an improved piston sub to
be used with a Type II Whip-Anchor. The dimensions of a similar sub
for a Type I or Type III Whip-Anchor will change, but only in OD/ID
of the sub. The internals will only vary slightly to fit the
different sub OD/ID. Thus, anybody skilled in the art will be able
to reproduce this tool for different sizes of Whip-Anchor. The
improved piston sub consists of a lower sub, 130, about 6 feet long
whose dimension is actually set by the volume of hydraulic fluid
needed to operate the chosen hydraulic packer; wherein, the ID at
the bottom of the lower sub is enlarged to form an enlarged piston
landing, 136. A piston, 131, having an o-ring and groove, 132, is
placed within the sub. This piston normally seals tightly against
the internal wall of the lower sub. The piston has a riser, 134,
which passes through the piston and is terminated in a removable
cap, 135. When the piston is within the normal bore of the sub, it
seals tightly against the wall: however, when the piston is in the
landing, 136, the o-ring seal is broken. The piston serves as an
interface between drilling mud and clean hydraulic fluid. There are
two 3/4 inch circulation channels, 133, that enhance the mud flow
past the piston after it reaches the landing.
It should be noted that a similar tool is commercially available,
but the commercial tool uses a particularly complex piston cage and
valve arrangement at the bottom of the lower sub in order to break
the seal between the two fluids. This particular caging arrangement
is unreliable because it is so complex. The inventor removed the
cage and "bored-back" the area where the cage had been positioned.
"Bore-back" is a term which means increasing the ID of a part to a
certain depth. In this case the inventor enlarged the ID of the
lower sub so that it was reasonably larger than the piston and
reasonably longer than the piston. These dimensions are not
critical--they must be chosen so that the piston, when it lands in
this region, no longer seals against the inner wall of the lower
sub.
The complete piston sub assembly, consisting of the upper (short)
and lower subs plus the piston riser generally is attached to the
setting tool and hydraulic connections made. The short sub, which
is only chain tight, is opened and the piston riser, 134, pulled up
to the top of the piston sub. The riser cap, 135, is opened and the
proper hydraulic fluid required by the hydraulic packer is poured
through the riser opening, 137, until the entire volume below the
piston, 131, is filled with hydraulic fluid. This volume includes
the packer, the hydraulic hose, and fittings in the Whip-Anchor,
setting tool. etc. The cap can be replaced along with the upper
stub which is then brought to the proper torque, or the riser cap
can be left off. If the riser cap is left off, the riser should be
filled with heavy lubricant. The heavy lubricant will act as a
removable plug or seal between the hydraulic fluid and the drilling
fluid, similar to the function performed by the riser cap.
The hydraulic packer is set, in the standard manner, by pressuring
the drilling fluid. Hydraulic setting pressure is transferred
through the piston ill the piston sub. Once the packer is set, the
hydraulic line is broken between the setting tool and the packer
leaving the entrained hydraulic fluid free to leave the piston sub.
The piston freely moves downward. When the piston reaches the
enlarged landing, the seal between the piston and the wall of the
lower sub is no longer functional and the drilling fluid will
proceed past the O-ring and out of the bottom of the piston sub,
through the broken hydraulic line and into the wellbore. If the
piston does not have channels, then the piston will seat on the
bottom of the sub (actually on set of threads belonging to the
lower tool) and inhibit fluid flow. If the riser cap is left out of
the assembly and the riser filled with heavy lubricant, the
drilling fluid will push the lubricant out of the riser and the
riser can provide a backup (or even primary) passage for the
drilling fluid.
Once the Whip-Anchor is in place, the hydraulic packer is set by
increasing the drilling mud pressure; this mud column pressure is
transferred to the hydraulic fluid through the piston sub and the
slips will move. As the hydraulic slips move, the fluid in the
piston sub will decrease and the piston, 131, will move towards the
landing. (A slight decrease in mud pressure is always observed when
this happens and this decrease tells the surface observers that the
hydraulic packer is beginning to set.) After the hydraulic packer
is set, the drill string is released from the Whip-Anchor by
pulling upward on the drill string, which shears the shear pin and
breaks the hydraulic connection to the Whip-Anchor face. As the
drill string is pulled upward, mud column pressure will force the
remaining hydraulic fluid from the piston sub and the piston will
land. This then allows drilling mud to readily flow around the
piston and out of the open/broken hydraulic hose, and the drill
pipe will drain as it is pulled out of the hole.
The actual setting procedure for the slew style Whip-Anchor will
now be discussed. The techniques for running the Whip-Anchor into
the well bore, be it used with a mechanical or hydraulic packer,
are the same as used in the current art. The Whip-Anchor service
representative need not worry as such about inadvertent pin shear
in pushing, because the setting tool rests firmly in the bottom of
the setting slot. Likewise, the Whip-Anchor service representative
need not won), about torsional pin shear because the setting tool
is contained by the side walls of the setting slot. These two
features will greatly enhance the probability of a successful set.
The Whip-Anchor service representative must still be concerned with
inadvertent pin shear while reciprocating the Whip-Anchor in order
to force the tool through a particularly tortuous path, for file
pill will shear as designed, with sufficient upward pull. Assuming
that the Whip-Anchor service representative has successfully
positioned the Whip-Anchor, that he has surveyed the tool face
orientation, and that he is in general satisfied with the
operation, all that remains is the set the packer-anchor.
The mechanical packer-anchor is set by slacking off on the drill
string and allowing the proper weight to rest on the setting tool.
This weight will be transferred to the Whip-Anchor where several
things will happen:
1) the torsional twist about the offset hinge will shear the spring
retaining pin, and
2) the transferred weight will cause the mechanical packer collet
to release, the weight will compress the packing elements and then
set the slips.
This operation is shown in FIG. 23, which illustrates the preferred
embodiment setting tool using the open tubular, 107, immediately
prior to setting the mechanical anchor-packer.
There are no hose connections between the open tubular, 107, and
the hydraulic passageway, 19, on the face of the whipstock. (Note,
if the operator were using this system in open hole and desired to
bottom wash, there would be a line between the tubular and the
whipstock passageway, as previously explained.) If the packer is
being used in an open (uncased) hole, the operation is similar,
except that mud anchors are used in the mechanical packer instead
of casing slips.
The hydraulic packer is set by well known standard procedures. This
operation is shown in FIG. 24, which illustrates the preferred
embodiment setting tool using the tubular, 102, with a short hose,
113S, connected between the tubular threaded opening, 107, and a
street-ell, 20, fitted in the hydraulic passageway, 19, on the face
of the whipstock. Simply stated, the mud pressure is increased. If
an MWD tool is in the bottom hole assembly, the associated pinned
by-pass valve will release, thus, shutting off mud circulation and
allowing mud pressure to increase. The increase in mud pressure is
applied to the piston sub, transferred to the hydraulic fluid and
onto to the hydraulic packer. The Whip-Anchor service
representative looks for the "pressure bobble", as previously
explained, which indicates that the hydraulic packer has begun to
set. The mud pressure is then increased to whatever pressure is
necessary to set the hydraulic anchor-packer.
Once the anchor-packer is set, be it mechanical or hydraulic, the
next step is to pull out of hole. In order to do this the
Whip-Anchor must be released from the setting tool and, hence, the
drill string. A number of well known steps are taken which do not
differ from the current art. Essentially, these steps are designed
to make certain that the anchor-packer has properly gripped the
casing or that the mud slips have firmly embedded the bore hole
(formation). The Whip-Anchor service representative generally pulls
and slacks off several times on the drill string maintaining the
strain each time for about a minute. If the mechanical packer
moves, the setting procedure should be repeated. If the hydraulic
packer moves, then the Whip-Anchor service representative should
follow the normal resetting procedure already practiced with this
type of packer. After assuring himself that the anchor-packer has
properly set, the Whip-Anchor service representative pulls back on
the drill string slowly, increasing the force until the shear pin
fractures. The situation for both types of packer is shown in FIGS.
25 and 26. Note that in FIG. 26, the short hydraulic hose, 113S,
breaks clear of the whipstock face taking the fractured street-ell,
20, with it. Fracturing of the street-ell, 20, at the face of the
whipstock at the point of the threads is assured by careful scoring
of the street-ell, 20, before or after it is placed ill the
whipstock during assembly.
Although the preferred embodiment of the setting tool is shown in
these illustrations, the alternative embodiment which uses a long
hydraulic hose, 113L, in place of the shorter hose, 113S, operates
in the same manner. Upon breaking away from the whipstock, the
longer hose will take the fractured street-ell. 20, with it. The
entire string is removed from the hole and the second pass tools
are prepared for the actual window mill cut.
TABLE 8 ______________________________________ SHEAR PULL VALVES
Whip-Anchor Approximate Size Bore size Shear Stud Size Shear Force*
______________________________________ I 31/2" 33/4"-51/2" 1/2"
.times. 1" 10, 15 & 20,000 OD length pounds II 51/2" 53/4"-8"
5/8" .times. 11/4" 20, 25 & 30,000 OD length pounds III 8"
81/4"-121/2" 3/4" .times. 11/2" 30, 35, 40 & OD length 45,000
pounds ______________________________________ *varies with
Whipanchor size
The approximate values of shear force is given in the table above.
It should be remembered that these values are only approximate and
the values seen at the surface will vary, depending on the well
bore conditions, hole length, etc. The actual shear value of the
shear stud will be determined by the shear groove that is cut in
the stud. The shear value is carefully chosen using techniques well
known in the industry and is set by the size and weight of the
Whip-Anchor (the whipstock and its anchor-packer), whether the
Whip-Anchor was to later be retrieved, and the hole conditions. For
example, a Type I tool with a retrievable hydraulic set anchor
packer, used for drilling 41/2 inch multiple drain holes, would
normally use a 10,000 pound shear stud if hole conditions were good
because the tool would be slated for retrieval. On the other hand,
a Type I tool used with a permanent hydraulic or mechanical packer
would use a 20,000 pound shear stud because the tool would not be
retrieved.
The second pass, the actual cutting of the window in the casing or
the start of the deviated hole in an uncased hole, is radically
different to the prior art. This invention differs from the prior
art in that there is no starting mill operation. In the prior art
and referring to FIG. 27A and FIG. 27B, a shear pin block, 40, was
always welded onto the surface of the whipstock tool face, 11,
within about one foot of the top, to which the shear pin was
bolted. The shear pin held the starter mill taper, 41, to the
block. The starter mill in turn was attached to the drill string
with necessary optional tools required for setting the whipstock.
Simply put, a similar procedure as described above was used to set
the whipstock. The only drawback being that the usual prior art
systems were designed to be used with hydraulic packers because
sufficient weight, to set a mechanical anchor packer, cannot be
imparted to the face of a whipstock through a shear pin.
For example, the minimum set down weights for good set on a
mechanical compression packer is as follows:
______________________________________ Type I size range 40,000
pounds Type II size range 60,000 pounds Type III size range 80,000
pounds ______________________________________
Thus, it can be seen that the prior art, which utilizes a shear pin
without a setting slot, cannot "set" compression mechanical packers
because the shear pin requirements are roughly one-half of the set
down requirements. There is one form of mechanical packer that uses
a single slip segment which results in a lower set down
requirement: however, the procedure for setting this particular
packer requires that weight be applied to the packer until the
shear pin shears. This means that the "set" of the packer cannot be
tested by pulling upward.
In the prior art the initial starter mill accomplished two
objectives:
1) the milling off of the shear pin block, 40; thus, preparing the
whipstock tool face, and
2) starting an initial up-slope cut, 99, into the casing (or
formation in an uncased hole).
The starter mill, 42, would push against the top of the whipstock
and be deflected into the side of the casing. An additional fulcrum
effect was obtained from the starting mill taper, 41, pushing
against the shear block, 40. (Please see prior art insets in FIGS.
23 through 27.) After the starter mill had traveled about 12 inches
into the hole, cutting a starter window of some 12 inches in the
casing (or formation in an uncased hole), the starter mill would
begin to mill the shear block. The maximum distance that the
starter mill could travel was about 20 inches before the starting
mill taper would hang tip on the casing and keep the starting mill
from moving along the required deviation path, 45. Quite often the
starter mill would cut into the whipstock tool face; thus, damaging
the necessary fulcrum point, 49, needed by the watermelon mill.
This device replaces the start milling operation with a simple
window mill, 48; the window mill being deflected by the deflector
head, 7.
The second pass downhole tool assembly consists of, a properly
sized window mill, 48, and a properly sized watermelon mill, 47, (a
second watermelon mill, 46, can be added by the operator if a
larger window opening was needed in the casing), as shown in FIGS.
27 and 28. These window mill tools are usually attached to a single
joint of heavy weight drill pipe to help ensure the proper fulcrum
effect: followed by the correct number of drill collars, which
provide the necessary milling weight. The prudent operator will add
a set of drilling jars which is followed by sufficient drill
collars to provide weight for the jars. The additional tools, drill
collars, subs and jars are not shown but are well known tools in
the practice.
FIG. 27 shows the start of the window milling operation. The window
mill, 48, is deflected against the casing (or formation), by the
deflector head, 7. The deflector head will carry the full weight of
the milling operation until the mill is able to cut into the casing
(or formation) at which time more and more mill weight will shift
to the well bore side. It is known that the starting mill will make
an initial cut into the casing, 99, and then begin to pull itself
into the casing riding tip onto the initial cut. Approximately the
first one foot of milling is the critical length, although this
distance will increase with the size of the hole. Please see the
deflector head parameter table, table 2. The actual milling
parameters are the same as the prior art uses after the initial
mill, thus, these techniques and parameters are well known by those
skilled in the art and need not be discussed in great detail. The
prior art is shown in FIGS. 27A and 27B.
As the window is cut in the casing, the window mill, 48, moves
downward and the watermelon mill, 47, begins to enlarge the casing
(or formation) cut. The watermelon mill fulcrums off the whipstock
tool face, (shown approximately as point 49) to help keep the
window mill on its deviation path. Additional fulcrum effects are
provided by the single joint of drill pipe (and second watermelon
mill, 46, if used) to guide the lower tools. The Whip-Anchor
service representative would normally use this set of tools to mill
the window and sufficient formation to obtain a total depth of
between seven and ten feet (a normal distance presently used in the
art). These tools would then be removed and a normal drilling
operation would commence on the next trip.
The Whip-Anchor is a retrievable tool which is a highly desired
characteristic for use in multiple drain holes or in multiple slim
hole exploration. The retrieval of the tool is made convenient
through a carefully designed fishing system based on field
experience. The major problem in retrieving tools (or any object)
from a well bore is being able to get a grip on the object so that
it can be withdrawn. The Whip-Anchor is retrievable because it has
a specially designed slot and retrieval tool (fishing tool) system
which allows for easier gripping of the tool. The operator should
properly prepare the hole for retrieval of the tool which should be
conducted by a qualified Whip-Anchor service representative. Proper
well bore preparation would include a trip with a locked up bottom
hole assembly and a good effort to sweep all drill cuttings, which
would have come from the newly deviated well bore, from the main
well bore.
The choice of downhole running tools for a retrieval operation is
based on myriad conditions and qualified Whip-Anchor Service
Representatives will have no problem in selecting the correct
combination of tools to be used with the Whip-Anchor retrieval
tool. A suggested centralized Bottom Hole Assembly (BHA)
arrangement is shown in FIG. 31, starting with the retrieval tool,
3. The retrieval tool should be followed by an unpinned by-pass
valve, 141, because the retrieval tool wash passage, 176, cannot
pass sufficient fluid flow to properly ensure drainage of drilling
fluid from the drill string when pulling out of hole. Proper
drainage of the drill string is essential to assure that mud is not
released on the drill floor. (As stated earlier, this device will
find its greatest use in old bores or in multiple drain bores which
use an oil based mud: considered toxic by the regulatory
authorities.) A full Gauge stabilizer, 118, would then follow. At
this point, the Whip-Anchor service representative can install an
MWD, 121, or all orientation sub, 126, with a single drill collar,
119. Either assembly can be used for orientation of the retrieval
hook in the hole, although an MWD tool would be preferred. Tile
orientation tool(s) are then followed by a second full gauge
stabilizer, 118. A set of jars, 140, is recommended plus the
necessary drill collars, 121, for the jars. For a Type I
While-Anchor, the Whip-Anchor service representative should use
20,000 pounds weight of drill collars: for the Type II tool, 40,000
pounds is recommended; and for the Type III tool, 60,000 pounds.
This complete centralized BHA would be attached to the drill
string, 120, and run into the well bore using standard
techniques.
The retrieval tool and BHA would be run into the well bore to just
above the top of the Whip-Anchor (see FIG. 15A). At this time the
Retrieval Tool Hook Face would be orientated to face the setting
and retrieval slots (See FIG. 15B). After orientation, the mud
pumps would be used, via the wash port, 175, to flush any debris
out of the setting slot, 13, and the retrieval slot, 12, on the
Whip-Anchor as the Retrieval tool proceeds downhole. The retrieval
hook passageway is designed to "scrub" the wall of the well bore
and the setting/retrieval slot for a more positive latch, and the
centralized BHA described above will ensure that this action indeed
happens. If the retrieval tool will not "scrub" due to extreme well
bore configurations, adjustments can be made to the tool in order
that it will properly "scrub." These adjusts could include adding a
bent sub assembly (not shown) between the retrieval tool, 3, and
the by-pass valve, 117. If worst comes to worst, the actual
retrieval tool could be bent.
Attempts would then be made, by reciprocating the drill string, to
latch the retrieval tool hook, 117, into the retrieval slot, 12.
(If an MWD tool is not used, the technique would still be similar,
the Whip-Anchor service representative just would not know which
way the hook and wash port were facing, and trial and error means
would have to be used to wash the slots and hook the retrieval
slot. That is reciprocate the drill string, rotate 15 degrees,
reciprocate the pipe, and repeat.) Positive latching of the hook in
the slot will be indicated at the surface by a sharp increase in
mud pressure because the mud flow through the wash port has been
stopped by the preferred use of the piston sleeve valve, 140, as
described previously. If, however, the alternate positive latch
indictor embodiments are used, mud flow will be stopped by closure
of the hook valve, 203, which is controlled by the hook valve
actuator, 204, being pushed inwards when the hook fully engages the
retrieval slot; or by closure of the flapper valve, 201, which is
controlled by the flapper valve actuator, 202, being pushed inwards
as the retrieval tool face presses against the setting slot. A
further indication of positive latching will be a "loss of weight"
if the Whip-Anchor service representative slacks off slightly, due
to the BHA weight being carried by the latched hook on the
retrieval tool. The Whip-Anchor service representative must
remember not to slack off greatly or the latch mechanism, 28, shear
pin will shear; this will be covered later in the discussion. After
the retrieval tool properly engages the retrieval slot, interaction
of the sloped slot and hook will draw the back of the Whip-Anchor
away from its close contact with the well bore as shown in FIG. 15D
as it rotates about the hinge assembly. (The hinge springs will
compress due to torsional forces about the offset hinge as the
anchor is dragged out of the hole.) This ensures that the top of
the Whip-Anchor will not catch against casing joints as it is
tripped out of the hole. Additionally, the extra length of the hook
that protrudes from the back of the Whip-Anchor, will aid in
reducing the possibility of snagging a casing joint.
Once the hook has engaged, the latch pin mechanism, 28, will ensure
that the hook does not come out of the retrieval slot if the
Whip-Anchor service representative has to reciprocate the drill
string in order to free the Whip-Anchor. Once hook engagement has
occurred, the Whip-Anchor service representative will slowly
increase the pull on the drill stem to the point of known slip
shear screw release force. The actual pull force will be greater
than the slip shear screw release force because of well bore
friction. Once the shear screws have sheared the slips on the
anchor will release, the packing will collapse, and the anchor will
free itself from the well bore. All that the Whip-Anchor service
representative must do is trip out of the well bore.
If the Whip-Anchor happens to stick in the hole during the trip,
the Whip-Anchor service representative can use the fishing jars to
attempt to work the Whip-Anchor free. The hydraulic fishing jars
must be reset, which is done by applying weight on the jars. The
retrieval tool latch pin mechanism, 28, (either embodiment as shown
in FIGS. 14A or 14B) is designed to provide sufficient strength
(i.e. it will not shear) for reset of the fishing jars. The
techniques for "fishing" stuck tools from a well bore are well
known and will not be discussed in this disclosure. On the other
hand, if the Whip-Anchor becomes irretrievably stuck, the
Whip-Anchor service representative may apply sufficient down
weight, which not only resets the jars, but will shear the latch
pin. This allows the retrieval tool hook, 117, to slide downward
and out of the retrieval slot. The drill string should then be
rotated and reciprocated in order to turn the retrieval hook away
from the retrieval slot. Following this, the drill string can be
tripped out of the hole and the stuck Whip-Anchor either abandoned
or retrieved using other well known and expensive fishing
techniques.
Finally, it must be realized the present art whipstocks using
hydraulic (or mechanical) anchor packers can be converted to
incorporate some of the salient features of the instant invention
and such conversion is considered to be within the scope of this
invention. The conversion may be made by cutting a setting tool
slot in the current state of the art whipstock and using the
techniques described above to set the converted whipstock attached
to either a mechanical or hydraulic packer. If the user desires, a
retrieval slot can be cut in the whipstock and the retrievable
features of the above disclosure can be used. It is recommended
that the top section of existing art whipstocks hardened to the
equivalent of the deflector head; or, alternatively that, the top
section of existing art whipstocks be cut and the deflector plate
of the instant invention be used in its place. Either
recommendation will ensure proper starting of the window cut. It
should be noted that converted whipstocks can only be used in the
size of well bore for which they were originally designed and will
have a "full bore" cross-section.
There has been disclosed heretofore in the above discussion the
best embodiment and best mode of the present invention presently
contemplated. It is to be understood that the examples given and
the dimensions may be changed, that dimensions are based on
strength properties of the material chosen to manufacture the
Whip-Anchor, and that modifications can be made thereto without
departing from the spirit of the present invention.
______________________________________ Invention Drawing Number
Index ______________________________________ Terminology = Two
conventional whipstocks are available. PACK-STOCK .TM. and BOTTOM
TRIP The Packstock is a whipstock and packer assembly combination
that forms a single integral unit downhole. Note that Pack-stock
.TM. is a trade name other trade names are used in the industry. In
this patent the term Whip-Anchor (or variants) will be used to
describe the combination of a whipstock and its anchor packer. The
bottom trip has a plunger that sticks out of the bottom of the
whipstock which when set down on the bottom of the hole will
release a spring loaded wedge/ slip which in turn sets the tool.
001 The Whipstock Invention generally - not including anchor-packer
002 The Whipstock Setting Tool generally 003 The Retrieval Tool
generally 004 Top section of whipstock generally 005 Bottom section
of whipstock generally 006 Hinge section of whipstock generally 007
Deflector head section of whipstock generally 008 The optional
spacer 009 Whipstock cut-a-way for hydraulic pressure line 010 The
complete downhole tool generally - whipstock, head, spacer, and
packer 011 The cupped face of the whipstock (tool face side) 012
Retrieval slot section of whipstock generally 013 Setting slot
section of whipstock generally 014H Hydraulic anchor packer
generally 014M Mechanical anchor packer generally 015 Cross-over
sub (between packer and whipstock) 016 Running tool (converts mud
pressure to hydraulic pressure 017 MWD tool 018 Other string tools
generally 019 Upper Hydraulic passageway - within whipstock 020
Hydraulic street-ell connection within whipstock face 021 Hydraulic
street-ell connection within whipstock back 022 Hydraulic
street-ell connection within whipstock base 023 Hydraulic line
within hydraulic cut-a-way 024 Base Hydraulic passageway - within
base 025 Setting slot base (or bottom) 026 Whipstock/deflector head
joint in general 027 Location of Retrieval Tool Shear Pin Aperture
or Mechanism 028 Retrieval Tool Latch Pin Mechanism in General 029
Conventional Whipstock Profile 030 Borehole generally - can be
cased or uncased 031 Casing 032 Cement between casing and formation
033 Upper Slips/Wedges 034 Lower Slips 035 Packing 036 Bridge Plug
037 Keeper Ring 038 Shear Pin Groove 039 Shear Pin 040 Prior Art -
Shear Pin Block 041 Prior Art - Starting Mill Taper 042 Prior Art -
Starting Mill 043 Prior Art - Shear Pin 044 Actual Deviated Bore
Hole 045 Planned Deviated Bore Hole 046 Second watermelon mill 047
First watermelon mill 048 Window Mill 049 Fulcrum Point
(approximate) on tool face 050 Leading edge of deflector plate 051
PCD Inserts 052 Joint between Deflector Head and Whipstock Body 053
Retainer Pins 054 Retainer Pin Hole 055 Deflector Head Sloped Side
056 Deflector Tool Face (continuation of 11) 057 Curved back of
Deflector Head 058 Deflector Head effective length 059 Deflector
Head Ridge 060 Deflector/whipstock joint backside weld gap 061 Weld
Bead 062 Shear Pin Aperture 063 Shear Pin Recess 064 Keeper Ring
Groove 065 Depth of Bottom/Base of Setting slot 066 Depth of
Retrieval slot 067 End of Tool Face 068 Threaded stud aperture - on
whipstock body 069 Whipstock/joint backside weld gap 070 Whipstock
Ridge 071 Whipstock Tool Face (continuation of 11) 072 Spacer
extended tool face (continuation of 11) 073 Spacer back 074 Spacer
Stud 075 Spacer Stud opening 076 Spacer base length 077 Spacer
depth 078 Spacer length 079 Spacer width 080 Hinge pin opening -
upper section 081 Hinge pin opening - base section 082 Hinge
section - upper section 083 Right Spring opening - upper section
084 Left Spring opening - upper section 085 Right spring opening -
base 086 Left spring opening - base 087 Hinge Pin 088 Spring
retainer shear pin 089 Sloped back of hinge base 090 Top sloped
back of hinge base 091 Hinge Pin snap ring 092 Hinge Pin Snap Ring
Grove 093 Spring retainer snap ring 094 spring retainer snap ring
grove 095 Hinge spring 096 Spring retainer shear pin opening -
upper section 097 Spring retainer shear pin opening - base section
098 Hinge section - base section 099 Casing Initial Cut Point 100
Setting Tool Sub 101 Setting Tool Rectangular Bar 102 Setting Tool
Fluid Line or Tubular 103 Weld between Bar and Fluid Line/Tubular
104 Weld between bar/line and sub 105 Shear Pin Threaded Aperture
in setting tool bar 106 Setting Tool bottom face angle 107 Open end
of fluid line - threaded female 108 Bottom Face of Setting Tool 109
Setting Tool Length (measured from sub) 110 Hydraulic Hose Male
Fitting 111 Setting Tube Recess or Offset 112 Setting Tool Threaded
Tubular Recess 113S Hydraulic Hose - Short (Preferred) 113L
Hydraulic Hose - Long (Alternate) 114 Stainless Steel Hydraulic
Hose Strap 115 116 Fishing Jars 117 By-pass Valve (unpinned) 118
Stabilizer 119 Single Drill Collar 120 Drill String 121 Drill
Collars 122 One Joint High Grade Drill Pipe 123 Combination of 120,
121 and 122 - upper string assembly 124 Cross-over sub 125
Cross-over sub 126 Orientation sub 127 MWD tool 128 Pinned by-pass
valve tool (or sub) 129 Short sub (for filling piston sub) 130
Lower Sub 131 Piston 132 Piston O'ring and Groove 133 Circulation
Channel(s) 134 Piston Riser 135 Riser Cap 136 Enlarged Piston
Landing 137 Riser Opening 138 139 Cross Passageway 140 Optional
Piston Valve (or Sleeve Valve) in General 141 Tool Joint 142 Tool
joint fluid passage 143 Hydraulic Street-ell 144 Hydraulic High
Pressure Hose 145 Buttress Threaded Connection for Access to Pistol
Valve 146 Piston valve 147 Piston valve rings 148 Piston valve
spring 149 Piston valve extension, attaches to retrieval tool 150
Heavy Arrows showing fluid flow 151 Piston valve Spline 152 Piston
valve Spline 153 piston valve Spline 154 Piston valve head 155
Lower piston valve sleeve 156 Upper piston valve sleeve 157 Piston
valve central fluid passage 158 Piston valve cross fluid passage
159 Piston valve seal point 160 The Retrieval Tool Generally (w/o
top works) 161 Lengths of Tool 162 " 163 " 164 " 165 " 166 " 167 "
168 Lengths of Tool 169 " 170 " 171 " 172 " 173 " 174 " 175 Wash
Port 176 Wash Passageway 177 Hook 178 Retrieval Bar 179 Retrieval
Tool Recess or Offset 180 Retrieval Tool Top Sub 181 Fluid
Passageway 182 Threaded opening 183 Retrieval Tool Hydraulic Hose
184 Stainless Steel Hydraulic Hose Retainer Clamp 185 Hydraulic
Street-ell 186 Threaded or Smooth Tubular Opening 187 Retrieval
Tool Tubular 188 Weld 189 Tubular Plug 190 Protector Plate 191 Tool
Joint 192 Tubular 193 Passageway 194 Threaded Connection 195
Flapper Valve Sleeve 196 Flapper Valve Passageway and Holder 197
Internal Fluid Passage 198 Curved lower bottom 199 Sloped face of
hook 200 Hook Weld to Tubular 201 Flapper Valve 202 Flapper valve
Actuator 203 Hook Valve 204 Hook Valve Actuator 205 Protector Plate
Weld Bead 206 Retrieval Tool Latch Pin 207 Retrieval Tool Latch
Spring 208 Retrieval Tool Latch Pin Retainer 209 Retrieval Tool
Latch Aperture - pin and spring side in WHIP-ANCHOR 210 Retrieval
Tool Latch Pin Opening - opening side in Retrieval Tool 211
Retrieval Tool Latch Aperture - pin and spring side in Retrieval
Tool 212 Retrieval Tool Latch Pin Opening - opening side in
WHIP-ANCHOR 213 ______________________________________
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